UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
 WASHINGTON, D.C. 20549
 FORM S-8
 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933
 
 UniSource Energy Corporation
  Arizona
    
    86-0786732(State or other Jurisdiction of
    
    (I.R.S. Employer Identification No.)Incorporation or Organization)
 One South Church Avenue, Suite 100
Tucson, Arizona 85701
 (Address of Principal Executive Offices and Zip Code)
 UniSource Energy Corporation 2011 Omnibus Stock and Incentive Plan
 Todd C. Hixon, Esq.
Vice President and General Counsel
UniSource Energy Corporation
One South Church Avenue, Suite 100
Tucson, Arizona 85701
(520) 571-4000
 (Name, Address and Telephone Number, Including Area Code, of Agent for Service)
  Large accelerated filer þ
    
    Accelerated filer o
    
    Non-accelerated filer o
    
    Smaller reporting company o(Do not check if a smaller reporting company)
 CALCULATION OF REGISTRATION FEE
 Proposed maximum
    
    
    Proposed maximumAmount to be
    
    
    offering price
    
    
    aggregate
    
    
    Amount ofTitle of securities to be registered
    
    
    registered
    
    
    per share
    
    
    offering price
    
    
    registration feeCommon Stock,
no par value
    
    
    1,340,000 shares (1)
    
    
    $
    36.26
    (2)
    
    
    $
    48,588,400
    (2)
    
    
    $
    5,642
 (1)
    
    Pursuant to Rule 416(a) under the Securities Act of 1933 (the Securities Act), this
Registration Statement also covers an indeterminate number of additional shares of Common
Stock that may be offered or issued to prevent dilution resulting from stock splits, stock
dividends or similar transactions as provided in the UniSource Energy Corporation 2011 Omnibus
Stock and Incentive Plan (the Plan). The amount to be registered includes the base
amount issuable pursuant to the Plan of 1,200,000 shares, plus an initial registration of
140,000 shares of the total number of shares, if any, that may become available for issuance
under the Plan upon the forfeiture, termination, cancelation, or expiration of awards
outstanding under the UniSource Energy Corporation 2006 Omnibus Stock and Incentive Plan, the
UniSource Energy Corporation 1994 Omnibus Stock and Incentive Plan, and the UniSource Energy
Corporation Amended and Restated 1994 Outside Directors Stock Option Plan.(2)
    
    Estimated solely for the purposes of calculating the registration fee, computed pursuant to
Rules 457(c) and (h) under the Securities Act on the basis of the average of the high and low
prices of a share of UniSource Energy Corporation Common Stock, as reported on the New York Stock
Exchange on June 15, 2011.




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PART I
INFORMATION REQUIRED IN THE SECTION 10(A) PROSPECTUS
 Item 1. Plan Information.*
 Item 2. Registrant Information and Employee Plan Annual Information.*
 Commission
 PART II
INFORMATION REQUIRED IN THE REGISTRATION STATEMENT
 Item 3. Incorporation of Documents by Reference
 UniSource
Energy Registrant Company Exchange Act
 (a)
    
    UniSource Energys Annual Report on Form 10-K (File No. 1-13739) for the fiscal
year ended December 31, 2010, filed with the Commission on March 1, 2011 and amended on
Form 10-K/A (File No. 1-13739), filed with the Commission on March 2, 2011;(b)
    
    UniSource Energys Quarterly Report on Form 10-Q (File No. 1-13739) for the
quarter ended March 31, 2011, filed with the Commission on May 2, 2011;(c)
    
    UniSource Energys Current Reports on Form 8-K (File Nos. 1-13739) filed with
the Commission on February 25, 2011, March 21, 2011, and May 11, 2011;(d)
    
    The description of UniSource Energys Common Stock contained in Form 8-A (File
No. 1-13739), filed with the Commission on December 23, 1997, and any amendment or
report filed for the purpose of updating such description, including Form 8-A Amendment
No. 1 filed on January 30, 1998 and Form 8-A Amendment No. 2 filed on January 30, 1998.
  Item 4. Description of Securities




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Item 5. Interests of Named Experts and Counsel
  Item 6. Indemnification of Directors and Officers




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Articles
  Item 7. Exemption From Registration Claimed
  Item 8. Exhibits
  Exhibit No.
    
    Description4.1
    
    
    Amended and Restated Articles of Incorporation of UniSource
Energy Corporation (incorporated by reference to Form 8-A/A,
dated January 30, 1998, File No. 1-13739  Exhibit 2(a))4.2
    
    
    Revised and Restated Bylaws of UniSource Energy Corporation,
as amended May 6, 2011 (incorporated by reference to Form 8-K,
filed with the Commission on May 11, 2011, File No. 1-13739
 Exhibit 3.1)4.3
    
    
    UniSource Energy Corporation 2011 Omnibus Stock and Incentive
Plan (incorporated by reference to Form 8-K, filed with the
Commission on May 11, 2011, File No. 1-13739  Exhibit
10.1)5.1
    
    
    Opinion of Counsel15.1
    
    
    Letter re unaudited interim financial information23.1
    
    
    Consent of PricewaterhouseCoopers LLP23.2
    
    
    Consent of Counsel (filed as part of Exhibit 5.1)24.1
    
    
    Power of Attorney (contained within the signature page hereto)




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Item 9. Undertakings
      provided, however
 bona fide
  bona fide




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SIGNATURES
  UNISOURCE ENERGY CORPORATIONBy:
    /s/ Paul J. BonaviaName:
    Paul J. BonaviaTitle:
    Chairman of the Board, President and Chief
Executive Officer
(Principal Executive Officer)By:
    /s/ Kevin P. LarsonName:
    Kevin P. LarsonTitle:
    Senior Vice President, Chief Financial Officer, and
Treasurer
(Principal Financial Officer)By:
    /s/ Karen G. KissingerName:
    Karen G. KissingerTitle:
    Vice President, Controller, and Chief Compliance
Officer
(Principal Accounting Officer)




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POWER OF ATTORNEY
   Signature
    
    
    
    Title
    
    DateLawrence J. Aldrich
    
    
    
    Director
    
    June 17, 2011/s/ Barbara M. Baumann

Barbara M. Baumann
    
    
    
    Director
    
    June 17, 2011/s/ Larry W. Bickle

Larry W. Bickle
    
    
    
    Director
    
    June 17, 2011/s/ Paul J. Bonavia

Paul J. Bonavia
    
    
    
    Director
    
    June 17, 2011/s/ Harold W. Burlingame

Harold W. Burlingame
    
    
    
    Director
    
    June 17, 2011/s/ Robert A. Elliott
    
    
    
    Director
    
    June 17, 2011Robert A. Elliott/s/ Daniel W. L. Fessler

Daniel W. L. Fessler
    
    
    
    Director
    
    June 17, 2011/s/ Louise L. Francesconi

Louise L. Francesconi
    
    
    
    Director
    
    June 17, 2011/s/ Warren Y. Jobe

Warren Y. Jobe
    
    
    
    Director
    
    June 17, 2011/s/ Ramiro G. Peru

Ramiro G. Peru
    
    
    
    Director
    
    June 17, 2011/s/ Gregory A. Pivirotto

Gregory A. Pivirotto
    
    
    
    Director
    
    June 17, 2011/s/ Joaquin Ruiz

Joaquin Ruiz
    
    
    
    Director
    
    June 17, 2011




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INDEX OF EXHIBITS
 Exhibit No.
    
    Description5.1
    
    
    Opinion of Counsel15.1
    
    
    Letter re unaudited interim financial information23.1
    
    
    Consent of PricewaterhouseCoopers LLP23.2
    
    
    Consent of Counsel (filed as part of Exhibit 5.1)24.1
    
    
    Power of Attorney (contained within the signature page hereto)