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                                                                       Exhibit 8

                          [Graham & Dunn PC Letterhead]

                                  June 23, 2006

Glacier Bancorp, Inc.
99 Commons Loop
Kalispell, Montana 59901

First National Bank of Morgan
120 North State Street
Morgan, Utah 84050

Re: BANK MERGER/TAX CONSEQUENCES

Ladies and Gentlemen:

This letter responds to your request for our opinion as to certain federal
income tax consequences of the proposed merger (the "Merger") of First National
Bank of Morgan ("Morgan") into New First National Bank of Morgan ("New Bank"), a
wholly-owned subsidiary of Glacier Bancorp, Inc. ("GBCI"), in exchange for cash
and the common stock of GBCI. The time at which the Merger becomes effective is
hereafter referred to as the "Effective Date." This opinion is being delivered
in connection with, and appears as an exhibit to, the Form S-4 Registration
Statement relating to the Merger that GBCI will file with the Securities and
Exchange Commission on or about June 29, 2006 (the "Registration Statement").

We have acted as legal counsel to GBCI and New Bank in connection with the
Merger. In such capacity, we have participated in the preparation of the "Plan
and Agreement of Merger Among First National Bank of Morgan, New First National
Bank of Morgan (Upon Formation) and Glacier Bancorp, Inc.," dated as of May 31,
2006 (the "Plan and Agreement of Merger") and the preparation and filing of the
Registration Statement. For purposes of rendering this opinion, we have examined
and relied upon originals, certified copies, or copies otherwise identified to
our satisfaction as being true copies of the originals of the following
documents, including all exhibits and schedules attached thereto:

     1.   The Plan and Agreement of Merger;

     2.   The Registration Statement; and

     3.   Such other documents, instruments, records and information pertaining
          to the Merger as we have deemed necessary for rendering our opinion.

We have assumed, without independent investigation or review, that the facts and
the representations and warranties contained in those documents (or otherwise
made known

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to us through the Effective Date of the Merger) are accurate and complete and
that the Merger will be effected in accordance with the terms of the Plan and
Agreement of Merger.

Our opinion is based on the U.S. Internal Revenue Code of 1986, as amended (the
"Code"), Treasury regulations, administrative interpretations, and judicial
precedents as of the date hereof. If there is any subsequent change in the
applicable law or regulations, or if there are subsequently any new applicable
administrative or judicial interpretations of the law or regulations, or if
there are any changes in the facts or circumstances surrounding the Merger, the
opinion expressed herein may become inapplicable.

Based upon our review of the facts described above and our analysis of the law,
and subject to the qualifications and limitations set forth herein, and the
completion of the transactions described in the manner contemplated by the Plan
and Agreement of Merger, it is our opinion that:

     1. The Merger will qualify as a reorganization within the meaning of IRC
Section 368(a)(1)(A) and will qualify as a "forward triangular merger" under IRC
Section 368(a)(2)(D).

     2. No gain or loss will be recognized by GBCI, New Bank or Morgan by reason
of the Merger.

     3. Holders of Morgan common stock who receive solely GBCI common stock in
exchange for their shares of Morgan common stock pursuant to the Merger will not
recognize gain or loss on the exchange. If any such stockholders receive cash in
lieu of a fractional share interest in GBCI common stock, such stockholders will
be treated as having received a fractional share of GBCI common stock in the
Merger and having immediately exchanged that fractional share for cash in a
taxable redemption by GBCI.

     4. Holders of Morgan common stock who receive solely cash in exchange for
their shares of Morgan common stock, and who own those shares as capital assets
and do not actually or constructively own shares of GBCI after the Merger, will
recognize capital gain or loss. The amount of such gain or loss will be equal to
the difference between the amount of cash received and the stockholder's
aggregate tax basis for such shares of Morgan common stock. The gain or loss
will be long-term capital gain or loss if such shares of Morgan common stock
were held for more than one year.

     5. A holder of Morgan common stock who receives both GBCI common stock and
cash consideration in exchange for his, her or its shares of Morgan common stock
will recognize gain, but not loss, to the extent of the lesser of the gain
realized by such stockholder in the exchange or the amount of cash received by
such stockholder in the exchange. Any gain recognized by a stockholder who owns
his, her or its shares of Morgan common stock as capital assets will be treated
as capital gain if the exchange is, with respect to the holder, either
"substantially disproportionate" or "not essentially equivalent to a dividend,"
each within the meaning of Code Section 302(b). The gain will be long-term
capital gain if the shares of Morgan common stock were held for more than one
year. The exchange will be "substantially disproportionate" with respect to a

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holder of Morgan common stock if, immediately after the Merger, the holder owns,
actually and constructively, less than 50% of the total combined voting power of
all classes of GBCI common stock entitled to vote and less than 80% of the
percentage of GBCI common stock actually and constructively owned by the holder
immediately before the Merger. For purposes of the foregoing determination, the
holder is treated as if (i) all its shares of Morgan common stock were first
exchanged in the Merger for shares of GBCI common stock, and (ii) a portion of
those shares of GBCI common stock were then redeemed for the cash actually
received in the Merger. Whether the exchange will be "not essentially equivalent
to a dividend" with respect to a holder of Morgan common stock will depend on
the holder's particular facts and circumstances.

We express our opinion herein only as to those matters specifically set forth
above. We do not express or infer an opinion as to the tax consequences of the
Merger under any state, local or foreign law, or with respect to other areas of
United States federal taxation. We are members of the Bar of the State of
Washington. We do not express or infer any opinion herein concerning any law
other than the federal law of the United States.

Our opinion is intended solely for the benefit of GBCI, New Bank, Morgan, and
the shareholders of Morgan. It may not be relied upon for any other purpose or
by any other person or entity or made available to any other person or entity
without our prior written consent.

We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and the reference to us in the Registration Statement
under the heading "Certain Federal Income Tax Consequences of the Merger." By
giving the foregoing consent, we do not admit that we come within the category
of persons whose consent is required under Section 7 of the Securities Act of
1933, as amended, or the rules and regulations of the Securities and Exchange
Commission thereunder.

                                         Sincerely,


                                         /s/ GRAHAM & DUNN PC
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