<PAGE>   1
                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549

                                    FORM 10-Q


[X]  QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
     EXCHANGE ACT OF 1934 FOR THE QUARTERLY PERIOD ENDED MARCH 31, 1997

                                              OR

[ ] TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
     EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM _________  TO ________


                         Commission file number 0-21518

                            IEA INCOME FUND XII, L.P.
             (Exact name of registrant as specified in its charter)


         CALIFORNIA                                        94-3143940
(State or other jurisdiction of                          (I.R.S. Employer
incorporation or organization)                           Identification No.)

         444 MARKET STREET, 15TH FLOOR, SAN FRANCISCO, CALIFORNIA 94111
               (Address of principal executive offices)     (Zip Code)

                                 (415) 677-8990
              (Registrant's telephone number, including area code)


Indicate by check mark whether the registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during
the preceding 12 months (or for such shorter period that the registrant was
required to file such reports), and (2) has been subject to such filing
requirements for the past 90 days. Yes X . No   .
                                      ----   ----



<PAGE>   2
                            IEA INCOME FUND XII, L.P.

                      REPORT ON FORM 10-Q FOR THE QUARTERLY
                           PERIOD ENDED MARCH 31, 1997

                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                                                 PAGE
<S>                                                                                                <C>
PART I - FINANCIAL INFORMATION

Item 1. Financial Statements

         Balance Sheets - March 31, 1997 (unaudited) and December 31, 1996                         4

         Statements of Operations for the three months ended March 31, 1997 and 1996 (unaudited)   5

         Statements of Cash Flows for the three months ended March 31, 1997 and 1996 (unaudited)   6

         Notes to Financial Statements (unaudited)                                                 7

Item 2. Management's Discussion and Analysis of Financial Condition and Results of                10
        Operations


PART II - OTHER INFORMATION

Item 6. Exhibits and Reports on Form 8-K                                                           13

</TABLE>



                                        2
<PAGE>   3

                         PART I - FINANCIAL INFORMATION


Item 1.   Financial Statements

          Presented herein are the Registrant's balance Sheets as of March 31,
          1997 and December 31, 1996, statements of operations for the three
          months ended March 31, 1997 and 1996, and statements of cash flows for
          the three months ended March 31, 1997 and 1996.




                                        3
<PAGE>   4

                            IEA INCOME FUND XII, L.P.

                                 BALANCE SHEETS

                                   (UNAUDITED)

<TABLE>
<CAPTION>

                                                                            March 31,       December 31,
                                                                               1997            1996
                                                                               ----            ----
<S>                                                                       <C>               <C>         
               Assets
               ------
Current assets:
   Cash and cash equivalents, includes $1,721,474 at March 31, 1997
      and $2,262,357 at December 31, 1996 in interest-bearing accounts    $  1,750,995      $  2,262,639
   Net lease receivables due from Leasing Company
      (notes 1 and 2)                                                        1,097,401         1,217,996
                                                                          ------------      ------------

         Total current assets                                                2,848,396         3,480,635
                                                                          ------------      ------------

Container rental equipment, at cost                                         63,500,454        63,140,873
   Less accumulated depreciation                                            16,876,941        15,961,254
                                                                          ------------      ------------
      Net container rental equipment                                        46,623,513        47,179,619
                                                                          ------------      ------------

Organizational costs, net                                                       85,327           145,611
                                                                          ------------      ------------

                                                                          $ 49,557,236      $ 50,805,865
                                                                          ============      ============
  Liabilities and Partners' Capital
  ---------------------------------
Current liabilities
   Accrued expenses                                                       $    462,948      $    462,948
   Due to general partner (notes 1 and 3)                                      163,382           238,382
                                                                          ------------      ------------

         Total current liabilities                                             626,330           701,330
                                                                          ------------      ------------

Partners' capital (deficit):
   General partner                                                             (27,930)          (25,428)
   Limited partners                                                         48,958,836        50,129,963
                                                                          ------------      ------------

         Total partners' capital                                            48,930,906        50,104,535
                                                                          ------------      ------------

                                                                          $ 49,557,236      $ 50,805,865
                                                                           ===========        ==========
</TABLE>

   The accompanying notes are an integral part of these financial statements.



                                        4
<PAGE>   5

                            IEA INCOME FUND XII, L.P.

                            STATEMENTS OF OPERATIONS

                                   (UNAUDITED)

<TABLE>
<CAPTION>

                                                                       Three Months Ended
                                                                ---------------------------
                                                                   March 31,         March 31,
                                                                     1997              1996
                                                                -----------       -----------
<S>                                                    <C>               <C>       
Net lease revenue (notes 1 and 4)                              $  1,396,464       $1,862,918

Other operating expenses:
  Depreciation                                                     986,575           984,261
  Other general and administrative expenses                         17,259            23,397
                                                               -----------        ----------
                                                                 1,003,834         1,007,658
                                                               -----------        ----------

    Earnings from operations                                       392,630           855,260

Other income:
  Interest income                                                   27,105            32,449
  Net gain on disposal of equipment                                  9,328            23,110
                                                               -----------        ----------
                                                                    36,433            55,559
                                                               -----------        ----------

    Net earnings                                               $   429,063        $  910,819
                                                               ===========        ==========

Allocation of net earnings:

  General partner                                              $    77,633        $  105,957
  Limited partners                                                 351,430           804,862
                                                               -----------        ----------

                                                               $   429,063        $  910,819
                                                               ===========        ==========

Limited partners' per unit share of net earnings               $       .10        $      .23
                                                               ===========        ==========

</TABLE>


   The accompanying notes are an integral part of these financial statements.



                                        5
<PAGE>   6

                            IEA INCOME FUND XII, L.P.

                            STATEMENTS OF CASH FLOWS

                                   (UNAUDITED)

<TABLE>
<CAPTION>
                                                                    Three Months Ended
                                                              ----------------------------
                                                                March 31,      March 31,
                                                                  1997           1996
                                                              ------------------------------
<S>                                                        <C>              <C>        
Net cash provided by operating activities                  $ 1,508,214      $ 1,804,482


Cash flows provided by (used in) investing activities:
  Proceeds from sale of container rental equipment              50,651          155,314
  Purchase of container rental equipment                      (374,111)        (221,850)
  Acquisition fees paid to general partner                     (93,706)        (231,093)
                                                           -----------      -----------


        Net cash used in investing activities                 (417,166)        (297,629)
                                                           -----------      -----------


Cash flows used in financing activities:
  Distribution to partners                                  (1,602,692)      (1,849,260)
                                                           -----------      -----------


Net decrease in cash and cash equivalents                     (511,644)        (342,407)


Cash and cash equivalents at January 1                       2,262,639        2,827,502
                                                           -----------      -----------


Cash and cash equivalents at March 31                      $ 1,750,995      $ 2,485,095
                                                           ===========      ===========

</TABLE>


   The accompanying notes are an integral part of these financial statements.



                                        6
<PAGE>   7

                            IEA INCOME FUND XII, L.P.

                     NOTES TO UNAUDITED FINANCIAL STATEMENTS


(1)  Summary of Significant Accounting Policies

     (a)  Nature of Operations

          IEA Income Fund XII, L.P. (the "Partnership") is a limited partnership
          organized under the laws of the State of California on August 28, 1991
          for the purpose of owning and leasing marine cargo containers. Cronos
          Capital Corp. ("CCC") is the general partner and, with its affiliate
          Cronos Containers Limited (the "Leasing Company"), manages and
          controls the business of the Partnership. The Partnership shall
          continue until December 31, 2011, unless sooner terminated upon the
          occurrence of certain events.

          The Partnership commenced operations on January 31, 1992, when the
          minimum subscription proceeds of $2,000,000 were obtained. As of March
          31, 1997, the Partnership operated 9,359 twenty-foot, 5,319 forty-foot
          and 209 forty-foot high-cube marine dry cargo containers, as well as
          199 twenty-foot and 306 forty-foot marine refrigerated cargo
          containers.

          The Partnership offered 3,750,000 units of limited partnership
          interest at $20 per unit, or $75,000,000. The offering terminated on
          November 30, 1992, at which time 3,513,594 limited partnership units
          had been purchased.


     (b)  Leasing Company and Leasing Agent Agreement

          The Partnership has entered into a Leasing Agent Agreement whereby the
          Leasing Company has the responsibility to manage the leasing
          operations of all equipment owned by the Partnership. Pursuant to the
          Agreement, the Leasing Company is responsible for leasing, managing
          and re-leasing the Partnership's containers to ocean carriers and has
          full discretion over which ocean carriers and suppliers of goods and
          services it may deal with. The Leasing Agent Agreement permits the
          Leasing Company to use the containers owned by the Partnership,
          together with other containers owned or managed by the Leasing Company
          and its affiliates, as part of a single fleet operated without regard
          to ownership. Since the Leasing Agent Agreement meets the definition
          of an operating lease in Statement of Financial Accounting Standards
          (SFAS) No. 13, it is accounted for as a lease under which the
          Partnership is lessor and the Leasing Company is lessee.

          The Leasing Agent Agreement generally provides that the Leasing
          Company will make payments to the Partnership based upon rentals
          collected from ocean carriers after deducting direct operating
          expenses and management fees to CCC and the Leasing Company. The
          Leasing Company leases containers to ocean carriers, generally under
          operating leases which are either master leases or term leases (mostly
          two to five years). Master leases do not specify the exact number of
          containers to be leased or the term that each container will remain on
          hire but allow the ocean carrier to pick up and drop off containers at
          various locations; rentals are based upon the number of containers
          used and the applicable per-diem rate. Accordingly, rentals under
          master leases are all variable and contingent upon the number of
          containers used. Most containers are leased to ocean carriers under
          master leases; leasing agreements with fixed payment terms are not
          material to the financial statements. Since there are no material
          minimum lease rentals, no disclosure of minimum lease rentals is
          provided in these financial statements.



                                                                     (Continued)

                                        7
<PAGE>   8

                            IEA INCOME FUND XII, L.P.

                     NOTES TO UNAUDITED FINANCIAL STATEMENTS


     (c)  Basis of Accounting

         The Partnership utilizes the accrual method of accounting. Net lease
         revenue is recorded by the Partnership in each period based upon its
         leasing agent agreement with the Leasing Company. Net lease revenue is
         generally dependent upon operating lease rentals from operating lease
         agreements between the Leasing Company and its various lessees, less
         direct operating expenses and management fees due in respect of the
         containers specified in each operating lease agreement.


     (d)  Financial Statement Presentation

          These financial statements have been prepared without audit. Certain
          information and footnote disclosures normally included in financial
          statements prepared in accordance with generally accepted accounting
          procedures have been omitted. It is suggested that these financial
          statements be read in conjunction with the financial statements and
          accompanying notes in the Partnership's latest annual report on Form
          10-K.

          The preparation of financial statements in conformity with generally
          accepted accounting principles (GAAP) requires the Partnership to make
          estimates and assumptions that affect the reported amounts of assets
          and liabilities and disclosure of contingent assets and liabilities at
          the date of the financial statements and the reported amounts of
          revenues and expenses during the reported period. Actual results could
          differ from those estimates.

          The interim financial statements presented herewith reflect all
          adjustments of a normal recurring nature which are, in the opinion of
          management, necessary to a fair statement of the financial condition
          and results of operations for the interim periods presented.


(2)  Net Lease Receivables Due from Leasing Company

     Net lease receivables due from the Leasing Company are determined by
     deducting direct operating payables and accrued expenses, base management
     fees payable, and reimbursed administrative expenses payable to CCC and its
     affiliates from the rental billings payable by the Leasing Company to the
     Partnership under operating leases to ocean carriers for the containers
     owned by the Partnership. Net lease receivables at March 31, 1997 and
     December 31, 1996 were as follows:

<TABLE>
<CAPTION>

                                                     March 31,     December 31,
                                                      1997           1996
                                                      ----           ----
<S>                                                <C>            <C>       
Lease receivables, net of doubtful accounts
   of $308,148 at March 31, 1997 and $318,136
   at December 31, 1996                            $2,335,123     $2,377,329
Less:
Direct operating payables and accrued expenses        746,126        634,032
Damage protection reserve                             169,256        196,373
Base management fees                                  282,488        282,898
Reimbursed administrative expenses                     39,852         46,030
                                                   ----------     ----------

                                                   $1,097,401     $1,217,996
                                                    =========      =========
</TABLE>



                                                                     (Continued)

                                        8
<PAGE>   9

                            IEA INCOME FUND XII, L.P.

                     NOTES TO UNAUDITED FINANCIAL STATEMENTS


(3) Net Lease Revenue

     Net lease revenue is determined by deducting direct operating expenses,
     base management fees and reimbursed administrative expenses to CCC and its
     affiliates from the rental revenue billed by the Leasing Company under
     operating leases to ocean carriers for the containers owned by the
     Partnership. Net lease revenue for the three-month periods ended March 31,
     1997 and 1996 was as follows:

<TABLE>
<CAPTION>

                                            Three Months Ended
                                            ------------------
                                         March 31,       March 31,
                                           1997            1996
                                       -----------    -----------
<S>                                     <C>            <C>       
Rental revenue                          $2,336,805     $2,816,426

Less:
Rental equipment operating expenses        659,668        606,934
Base management fees                       161,762        192,140
Reimbursed administrative expenses         118,911        154,434
                                        ----------     ----------

                                        $1,396,464     $1,862,918
                                        ==========     ==========
</TABLE>




                                        9
<PAGE>   10

Item 2. Management's Discussion and Analysis of Financial Condition and Results
        of Operations

It is suggested that the following discussion be read in conjunction with the
Registrant's most recent annual report on Form 10-K.

1)   Material changes in financial condition between March 31, 1997 and December
     31, 1996.

     At March 31, 1997, the Registrant had $1,750,995 in cash and cash
     equivalents, a decrease of $511,644 from the December 31, 1996 cash
     balances. During the first quarter of 1997, the Registrant expended
     $374,111 of cash generated from sales proceeds to pay for containers
     purchased from the general partner during the first quarter of 1997. At
     March 31, 1997, the Registrant had approximately $25,000 in cash generated
     from equipment sales reserved as part of its cash balances. Throughout the
     remainder of 1997, the Registrant expects to continue using cash generated
     from equipment sales to purchase and replace containers which have been
     lost or damaged beyond repair.

     Net lease receivables at March 31, 1997 declined 10% when compared to
     December 31, 1996. Contributing to this change was an increase in direct
     operating payables and accrued expenses, a component of net lease
     receivables. Direct operating payables and accrued expenses increased 17%
     from December 31, 1996 due to the increase in costs associated with lower
     utilization levels, including handling, storage and repositioning.

     The Registrant's cash distribution from operations for the first quarter of
     1997 was 8.5% (annualized) of the limited partners' original capital
     contribution, a decline from 9.0% (annualized) for the fourth quarter of
     1996. These distributions are directly related to the Registrant's results
     from operations and may fluctuate accordingly.

     During 1996, ocean carriers and other transport companies moved away from
     leasing containers outright, as declining container prices, favorable
     interest rates and the abundance of available capital resulted in ocean
     carriers and transport companies purchasing a larger share of equipment for
     their own account, reducing the demand for leased containers. Once the
     demand for leased containers began to fall, per-diem rental rates were also
     adversely affected. These conditions continued to exist throughout the
     first quarter of 1997, contributing to a decline in the Registrant's
     average dry cargo container utilization rate of 77% at December 31, 1996 to
     76% at March 31, 1997. The Registrant's refrigerated container utilization
     rate was 86% at March 31, 1997, unchanged from December 31, 1996. The
     Leasing Company continues to implement various marketing strategies,
     including but not limited to, offering incentives to shipping companies,
     repositioning containers to high demand locations and focusing towards term
     leases and other leasing opportunities including the leasing of containers
     for local storage, in order to counter current leasing market conditions.
     These conditions are expected to continue throughout 1997, impacting the
     Registrant's liquidity and capital resources.


2)   Material changes in the results of operations between the three-month
     period ended March 31, 1997 and the three-month period ended March 31,
     1996.

     Net lease revenue for the first quarter of 1997 was $1,396,464, a decline
     of approximately 25% from the first quarter of 1996. Gross rental revenue
     (a component of net lease revenue) for the quarter ended March 31, 1997 was
     $2,336,805, reflecting a decline of 17% from the same three-month period in
     1996. Gross rental revenue was primarily impacted by the sluggish market
     conditions that existed during 1996 and throughout the first quarter of
     1997. These conditions contributed to lower average dry cargo and
     refrigerated utilization rates. Average dry cargo and refrigerated
     container per-diem rental rates for the three-month period ended March 31,
     1997 declined 9% and 6%, respectively, when compared to the same period in
     the prior year.



                                       10
<PAGE>   11

     The Registrant's average fleet size and utilization rates for the
     three-month periods ended March 31, 1997 and 1996 were as follows:

<TABLE>
<CAPTION>
                                                             Three Months Ended
                                                       ---------------------------
                                                          March 31,     March 31,
                                                             1997         1996
                                                      -----------------------------
           <S>                                              <C>               <C>
          Average Fleet Size (measured in
             twenty-foot equivalent units (TEU))
                Dry cargo containers                       20,299            20,317
               Refrigerated containers                       811               813
          Average Utilization
                Dry cargo containers                          76%               83%
                Refrigerated containers                       85%               91%
</TABLE>


     Rental equipment operating expenses were 28% of the Registrant's gross
     lease revenue during the three-month period ended March 31, 1997, as
     compared to 22% during the three-month period ended March 31, 1996. This
     increase was largely attributable to an increase in costs associated with
     lower utilization levels, including handling, storage and repositioning.

     The Registrant disposed of four twenty-foot and five forty-foot dry cargo
     containers during the first quarter of 1997, as compared to 24 twenty-foot,
     15 forty-foot and two high-cube dry cargo containers during the same period
     in the prior year.

     As reported in the Registrant's Current Report on Form 8-K and Amendment
     No. 1 to Current Report on Form 8-K, filed with the Commission on February
     7, 1997 and February 26, 1997, respectively, Arthur Andersen, London,
     England, resigned as auditors of The Cronos Group, a Luxembourg Corporation
     headquartered in Orchard Lea, England (the "Parent Company"), on February
     3, 1997.

     The Parent Company is the indirect corporate parent of Cronos Capital
     Corp., the General Partner of the Registrant. In its letter of resignation
     to the Parent Company, Arthur Andersen states that it resigned as auditors
     of the Parent Company and all other entities affiliated with the Parent
     Company. While its letter of resignation was not addressed to the General
     Partner or the Registrant, Arthur Andersen confirmed to the General Partner
     that its resignation as auditors of the entities referred to in its letter
     of resignation included its resignation as auditors of Cronos Capital Corp.
     and the Registrant.

     The Registrant does not, at this time, have sufficient information to
     determine the impact, if any, that the concerns expressed by Arthur
     Andersen in its letter of resignation may have on the future operating
     results and financial condition of the Registrant or the Leasing Company's
     ability to manage the Registrant's fleet in subsequent periods. However,
     the General Partner of the Registrant does not believe, based upon the
     information currently available to it, that Arthur Andersen's resignation
     was triggered by any concern over the accounting policies and procedures
     followed by the Registrant.

     Arthur Andersen's report on the financial statements of Cronos Capital
     Corp. and the Registrant, for either of the past two years, has not
     contained an adverse opinion or a disclaimer of opinion, nor was any such
     report qualified or modified as to uncertainty, audit scope, or accounting
     principles.

     During the Registrant's two most recent fiscal years and the subsequent
     interim period preceding Arthur Andersen's resignation, there have been no
     disagreements between Cronos Capital Corp. or the Registrant and Arthur
     Andersen on any matter of accounting principles or practices, financial
     statement disclosure, or auditing scope or procedure.

     Due to the nature and timing of Arthur Andersen's resignation, the Parent
     Company and General Partner were unable to name a successor auditor on
     behalf of the Registrant until it retained Moore Stephens, P.C. ("Moore
     Stephens") on April 10, 1997, as reported in the Registrant's Current
     Report on Form 8-K, filed April 14, 1997.



                                       11
<PAGE>   12

     Cautionary Statement

     This Quarterly Report on Form 10-Q contains statements relating to future
     results of the Registrant, including certain projections and business
     trends, that are "forward-looking statements" as defined in the Private
     Securities Litigation Reform Act of 1995. Actual results may differ
     materially from those projected as a result of certain risks and
     uncertainties, including but not limited to changes in: economic
     conditions; trade policies; demand for and market acceptance of leased
     marine cargo containers; competitive utilization and per-diem rental rate
     pressures; as well as other risks and uncertainties, including but not
     limited to those described in the above discussion of the marine container
     leasing business under Item 2., Management's Discussion and Analysis of
     Financial Condition and Results of Operations; and those detailed from time
     to time in the filings of Registrant with the Securities and Exchange
     Commission.



                                       12
<PAGE>   13

                           PART II - OTHER INFORMATION


Item 6. Exhibits and Reports on Form 8-K

(a)  Exhibits

<TABLE>
<CAPTION>

Exhibit
   No.                         Description                                       Method of Filing
-------------------------------------------------------------------              ----------------
<S>          <C>                                                                 <C>    
  3(a)       Limited Partnership Agreement of the Registrant, amended and        *
             restated as of December 2, 1991

  3(b)       Certificate of Limited Partnership of the Registrant                **

  10         Form of Leasing Agent Agreement with Cronos Containers Limited      ***

  27         Financial Data Schedule                                             Filed with this document

</TABLE>


(b)  Reports on Form 8-K

     The Registrant filed a Report on Form 8-K, dated February 7, 1997 and
     Amendment No. 1 to Report on Form 8-K dated February 26, 1997, reporting
     the resignation of the Registrant's certifying accountant.

     The Registrant filed a Report on Form 8-K, April 14, 1997, reporting the
     appointment of the Registrant's successor certifying accountant.




--------------

*    Incorporated by reference to Exhibit "A" to the Prospectus of the
     Registrant dated December 2, 1991, included as part of Registration
     Statement on Form S-1 (No. 33-42697)

**   Incorporated by reference to Exhibit 3.2 to the Registration Statement on
     Form S-1 (No. 33-42697)

***  Incorporated by reference to Exhibit 10.2 to the Registration Statement on
     Form S-1 (No. 33-42697)



                                       12
<PAGE>   14

                                   SIGNATURES


     Pursuant to the requirements of the Securities Exchange Act of 1934, the
Registrant has duly caused this Report to be signed on its behalf by the
undersigned thereunto duly authorized.



                                   IEA INCOME FUND XII, L.P.

                                   By   Cronos Capital Corp.
                                        The General Partner



                                   By   /s/ JOHN KALLAS
                                        --------------------------------------
                                        John Kallas
                                        Vice President, Treasurer
                                        Principal Finance & Accounting Officer



Date:  June 16, 1997



                                       13
<PAGE>   15

                                  EXHIBIT INDEX

<TABLE>
<CAPTION>

Exhibit
   No.                         Description                                       Method of Filing
-------                        -----------                                       ----------------
<S>          <C>                                                                 <C>    
  3(a)       Limited Partnership Agreement of the Registrant, amended and        *
             restated as of December 2, 1991

  3(b)       Certificate of Limited Partnership of the Registrant                **

  10         Form of Leasing Agent Agreement with Cronos Containers Limited      ***

  27         Financial Data Schedule                                             Filed with this document

</TABLE>






-------------

*    Incorporated by reference to Exhibit "A" to the Prospectus of the
     Registrant dated December 2, 1991, included as part of Registration
     Statement on Form S-1 (No. 33-42697)

**   Incorporated by reference to Exhibit 3.2 to the Registration Statement on
     Form S-1 (No. 33-42697)

***  Incorporated by reference to Exhibit 10.2 to the Registration Statement on
     Form S-1 (No. 33-42697)