<PAGE>

                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                  SCHEDULE 13G

                    Under the Securities Exchange Act of 1934

                             (Amendment No. ____)*

                         DiamondRock Hospitality Company
                                (Name of Issuer)

                                  Common Stock
                         (Title of Class of Securities)

                                    252784301
                                 (CUSIP Number)

                                December 31, 2006
             (Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule
is filed:

     [X]  Rule 13d-1(b)

     [ ]  Rule 13d-1(c)

     [ ]  Rule 13d-1(d)

*    The remainder of this cover page shall be filled out for a reporting
     person's initial filing on this form with respect to the subject class of
     securities, and for any subsequent amendment containing information which
     would alter the disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).


<PAGE>

                                  SCHEDULE 13G

CUSIP No. 252784301

--------------------------------------------------------------------------------
1.   Names of Reporting Persons.

     I.R.S. Identification Nos. of above persons (entities only).

     AMVESCAP PLC
     INVESCO Institutional (N.A.), Inc.
     PowerShares Capital Management LLC
--------------------------------------------------------------------------------
2.   Check the Appropriate Box if a Member of a Group (see Instructions)

     (a) [ ]
     (b) [ ]
--------------------------------------------------------------------------------
3.   SEC Use Only

--------------------------------------------------------------------------------
4.   Citizenship or Place of Organization

     AMVESCAP PLC: England
     INVESCO Institutional (N.A.), Inc. United States
     PowerShares Capital Management LLC United States
--------------------------------------------------------------------------------
               5.   Sole Voting Power 3,983,126: Such shares are held by the
                    following entities in the respective amounts listed:

                    INVESCO Institutional (N.A.), Inc. 3,981,536
                    PowerShares Capital Management LLC 1,590
  Number of    -----------------------------------------------------------------
   Shares      6.   Shared Voting Power
Beneficially
    Owned           -0-
   by Each     -----------------------------------------------------------------
  Reporting    7.   Sole Dispositive Power 3,983,126: Such shares are held by
 Person With        the following entities in the respective amounts listed:

                    INVESCO Institutional (N.A.), Inc. 3,981,536
                    PowerShares Capital Management LLC 1,590
               -----------------------------------------------------------------
               8.   Shared Dispositive Power

                    -0-
--------------------------------------------------------------------------------
9.   Aggregate Amount Beneficially Owned by Each Reporting Person

     3,983,126
--------------------------------------------------------------------------------
10.  Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See
     Instructions)

     N/A
--------------------------------------------------------------------------------
11.  Percent of Class Represented by Amount in Row (9)

     5.23%
--------------------------------------------------------------------------------
12.  Type of Reporting Person (See Instructions)

     IA, HC. See Items 2 and 3 of this statement.
--------------------------------------------------------------------------------


<PAGE>

                                  SCHEDULE 13G

Item 1(a)   Name of Issuer:

            DiamondRock Hospitality Company

Item 1(b)   Address of Issuer's Principal Executive Offices:

            6903 Rockledge Drive
            Suite 800
            Bethesda, MD 20817

Item 2(a)   Name of Person Filing:

            AMVESCAP PLC

            In accordance with Securities and Exchange Commission Release No.
            34-39538 (January 12, 1998), this statement on Schedule 13G or
            amendment thereto is being filed by AMVESCAP PLC ("AMVESCAP"), a
            U.K. entity, on behalf of itself and its subsidiaries listed in Item
            4 of the cover of this statement. AMVESCAP through such subsidiaries
            provides investment management services to institutional and
            individual investors worldwide.

            Executive officers and directors of AMVESCAP or its subsidiaries may
            beneficially own shares of the securities of the issuer to which
            this statement relates (the "Shares"), and such Shares are not
            reported in this statement. AMVESCAP and its subsidiaries disclaim
            beneficial ownership of Shares beneficially owned by any of their
            executive officers and directors. Each of AMVESCAP's direct and
            indirect subsidiaries also disclaim beneficial ownership of Shares
            beneficially owned by AMVESCAP and any other subsidiary.

Item 2(b)   Address of Principal Business Office:

            30 Finsbury Square
            London EC2A 1AG
            England

Item 2(c)   Citizenship:

            See the response to Item 2(a) of this statement.

Item 2(d)   Title of Class of Securities:

            Common Stock, $.01 par value per share

Item 2(e)   CUSIP Number:

            252784301

Item 3      If this statement is filed pursuant to ss240.13d-1(b) or
            240.13d-2(b) or (c), check whether the person filing is a:

      (e)   [x]   An investment adviser in accordance with section
                  240.13d-1(b)(1)(ii)(E)

      (g)   [x]   A parent holding company or control person in accordance with
                  section 240.13d-1(b)(1)(ii)(G)

            As noted in Item 2 above, AMVESCAP is making this filing on behalf
            of its subsidiaries listed herein. Each of these entities is either
            an investment adviser registered with the United States Securities
            and Exchange Commission under Section 203 of the Investment Advisers
            Act of 1940, as amended, or under similar laws of other
            jurisdictions. AMVESCAP is a holding company.


<PAGE>

Item 4      Ownership:

            Please see responses to Items 5-8 on the cover of this statement,
            which are incorporated herein by reference.

Item 5      Ownership of Five Percent or Less of a Class:

            If this statement is being filed to report the fact that as of the
            date hereof the reporting person has ceased to be the beneficial
            owner of more than five percent of the class of securities, check
            the following [ ]

Item 6      Ownership of More than Five Percent on Behalf of Another Person:

            N/A

Item 7      Identification and Classification of the Subsidiary Which Acquired
            the Security Being reported on By the Parent Holding Company:

            Please see Item 3 of this statement, which is incorporated herein by
            reference.

Item 8      Identification and Classification of Members of the Group:

            N/A

Item 9      Notice of Dissolution of a Group:

            N/A

Item 10     Certification:

            By signing below I certify that, to the best of my knowledge and
            belief, the securities referred to above were acquired and are held
            in the ordinary course of business and were not acquired and are not
            held for the purpose of or with the effect of changing or
            influencing the control of the issuer of the securities and were not
            acquired and are not held in connection with or as a participant in
            any transaction having that purpose or effect.

            Signature:

            After reasonable inquiry and to the best of my knowledge and belief,
            I certify that the information set forth in this statement is true,
            complete and correct.

                                        02/14/2007
                                        Date

                                        AMVESCAP PLC


                                        By: /s/ Lisa Brinkley
                                            ------------------------------------
                                            Lisa Brinkley
                                            Chief Compliance Officer


<PAGE>

                                  Exhibit Index

Exhibit A Joint Filing Agreement




<PAGE>

                                    EXHIBIT A

                             JOINT FILING AGREEMENT

In accordance with Rule 13d-1(k)(l) under the Securities Exchange Act of 1934,
as amended, the undersigned hereby agree to the joint filing of the attached
Schedule 13G, and any and all amendments thereto, and expressly authorize
AMVESCAP PLC, as the ultimate parent company of each of its undersigned
subsidiaries, to file such Schedule 13G, and any and all amendments thereto, on
behalf of each of them.

Dated: February 14, 2007                AMVESCAP PLC


                                        By: /s/ Lisa Brinkley
                                            ------------------------------------
                                        Name: Lisa Brinkley
                                        Title: SVP/Global Compliance Director


                                        AIM Advisors, Inc.


                                        By: /s/ Todd L. Spillane
                                            ------------------------------------
                                        Name: Todd L. Spillane
                                        Title: Chief Compliance Officer


                                        AIM Capital Management, Inc.


                                        By: /s/ Todd L. Spillane
                                            ------------------------------------
                                        Name: Todd L. Spillane
                                        Title: Chief Compliance Officer


                                        AIM Funds Management, Inc.


                                        By: /s/ Wayne Bolton
                                            ------------------------------------
                                        Name: Wayne Bolton
                                        Title: Vice President, Compliance &
                                               Chief Compliance Officer


                                        AIM Private Asset Management, Inc.


                                        By: /s/ Todd L. Spillane
                                            ------------------------------------
                                        Name: Todd L. Spillane
                                        Title: Chief Compliance Officer


                                        AMVESCAP National Trust Company


                                        By: /s/ Kevin Lyman
                                            ------------------------------------
                                        Name: Kevin Lyman
                                        Title: General Counsel


                                        Atlantic Trust Company, N.A.


                                        By: /s/ Kathleen Oldenborg
                                            ------------------------------------
                                        Name: Kathleen Oldenborg
                                        Title: Ghief Compliance Officer


                                        INVESCO Hong Kong Limited


                                        By: /s/ Asha Balachandra

                                            ------------------------------------
                                        Name: Asha Balachandra
                                        Title: Reg. Head of Legal AP


<PAGE>

                                        INVESCO Asset Management Deutschland
                                        GmbH


                                        By: /s/ Stephanie Ehrenfried
                                            ------------------------------------
                                        Name: Stephanie Ehrenfried
                                        Title: Head of Legal CE


                                        INVESCO Asset Management Limited


                                        By: /s/ Nick Styman
                                            ------------------------------------
                                        Name: Nick Styman
                                        Title: Director of European Compliance


                                        INVESCO Asset Management S.A.


                                        By: /s/ Patrick Riviere
                                            ------------------------------------
                                        Name: Patrick Riviere
                                        Title: Managing Director


                                        INVESCO Asset Management Osterreich GmbH


                                        By: /s/ Thomas Kraus
                                            ------------------------------------
                                        Name: Thomas Kraus
                                        Title: Managing Director


                                        INVESCO Global Asset Management (N.A.),
                                        Inc.


                                        By: /s/ Jeffrey Kupor
                                            ------------------------------------
                                        Name: Jeffrey Kupor
                                        Title: General Counsel


                                        INVESCO GT Management Company S.A.


                                        By: /s/ Nick Styman
                                            ------------------------------------
                                        Name: Nick Styman
                                        Title: Director of European Compliance


                                        INVESCO Institutional (N.A.), Inc.


                                        By: /s/ Jeffrey Kupor
                                            ------------------------------------
                                        Name: Jeffrey Kupor
                                        Title: General Counsel


                                        INVESCO Management S.A.


                                        By: /s/ Alain Gerbaldi
                                            ------------------------------------
                                        Name: Alain Gerbaldi
                                        Title: Head of Investment Operations


                                        INVESCO Maximum Income Management S.A.


                                        By: /s/ Alain Gerbaldi
                                            ------------------------------------
                                        Name: Alain Gerbaldi
                                        Title: Head of Investment Operations


                                        INVESCO Private Capital, Inc.


                                        By: /s/ Jeffrey Kupor
                                            ------------------------------------
                                        Name: Jeffrey Kupor
                                        Title: General Counsel


<PAGE>

                                        INVESCO Senior Secured Management, Inc.


                                        By: /s/ Jeffrey Kupor
                                            ------------------------------------
                                        Name: Jeffrey Kupor
                                        Title: General Counsel


                                        INVESCO Taiwan Limited


                                        By: /s/ Asha Balachandra
                                            ------------------------------------
                                        Name: Asha Balachandra
                                        Title: Reg. Head of Legal, AP


                                        INVESCO Asset Management (Japan) Limited


                                        By: /s/ Asha Balachandra
                                            ------------------------------------
                                        Name: Asha Balachandra
                                        Title: Reg. Head of Legal, AP


                                        INVESCO Asset Management Ireland Limited


                                        By: /s/ Alain Gerbaldi
                                            ------------------------------------
                                        Name: Alain Gerbaldi
                                        Title: Head of Investment Operations


                                        INVESCO Kapitalanlagegesellschaft GmbH


                                        By: /s/ Stephanie Ehrenfried
                                            ------------------------------------
                                        Name: Stephanie Ehrenfried
                                        Title: Head of Legal CE


                                        PowerShares Capital Management LLC


                                        By: /s/ Kevin Gustafson
                                            ------------------------------------
                                        Name: Kevin Gustafson
                                        Title: General Counsel & COO


                                        Stein Roe Investment Counsel, Inc.


                                        By: /s/ Greg Campbell
                                            ------------------------------------
                                        Name: Greg Campbell
                                        Title: General Counsel