UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K/A

(Amendment No. 1)

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the

Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): May 30, 2012

Terreno Realty Corporation

(Exact name of registrant as specified in its charter)

101 Montgomery Street, Suite 200

San Francisco, CA 94104

(Address of principal executive offices) (Zip Code)

(415) 655-4580

(Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

This Form 8-K/A amends and supplements the registrant’s Form 8-K, filed on May 31, 2012 reporting the acquisition of Garfield (the “Initial Report”), to include the historical financial statements and pro forma financial information required by Item 9.01(a) and (b) of Form 8-K. This Form 8-K/A should be read in conjunction with the Initial Report. This 8-K/A also includes the historical financial statements of Caribbean, which was acquired on July 3, 2012 and for which we are also filing a Form 8-K/A.

(d) Exhibits

Report of Independent Auditor

The Board of Directors and Stockholders of

Terreno Realty Corporation

San Francisco, California

We have audited the accompanying statement of revenues and certain expenses of Garfield (the “Property”) for the year ended December 31, 2011. This statement of revenues and certain expenses is the responsibility of the Company’s management. Our responsibility is to express an opinion on this statement based on our audit.

We conducted our audit in accordance with auditing standards generally accepted in the United States. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the statement of revenues and certain expenses is free of material misstatement. We were not engaged to perform an audit of the Property’s internal control over financial reporting. Our audit included consideration of internal control over financial reporting as a basis for designing audit procedures that are appropriate in the circumstances, but not for the purpose of expressing an opinion on the effectiveness of the Property’s internal control over financial reporting. Accordingly, we express no such opinion. An audit also includes assessing the basis of accounting used and significant estimates made by management, as well as evaluating the overall statement presentation. We believe that our audit provides a reasonable basis for our opinion.

The accompanying statement of revenues and certain expenses of the Property was prepared for the purpose of complying with the rules and regulations of the Securities and Exchange Commission for inclusion in the Form 8-K/A of Terreno Realty Corporation as described in Note 1, and is not intended to be a complete presentation of the Property’s revenues and expenses.

In our opinion, the statement of revenues and certain expenses referred to above presents fairly, in all material respects, the revenues and certain expenses described in Note 1 of Garfield for the year ended December 31, 2011, in conformity with U.S. generally accepted accounting principles.

/s/ Ernst & Young LLP

San Francisco, California

July 27, 2012

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Garfield

Statements of Revenues and Certain Expenses

For the Period from January 1, 2012 to April 30, 2012 (unaudited)

and the Year Ended December 31, 2011

(in thousands)

See accompanying notes to statements of revenues and certain expenses.

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Garfield

Notes to Statements of Revenues and Certain Expenses

For the Period from January 1, 2012 to April 30, 2012 (unaudited)

and the Year Ended December 31, 2011

The accompanying statements of revenues and certain expenses present the results of operations of Garfield (the “Property”) for the period from January 1, 2012 to April 30, 2012 and the year ended December 31, 2011. The Property was acquired by a wholly-owned subsidiary of Terreno Realty Corporation from a third-party seller, Dune-Westcore GBP, LLC, on May 30, 2012 for approximately $52.4 million. The Property is located in Commerce, California and consists of five multi-tenant industrial buildings containing 545,299 square feet (unaudited), which were approximately 79% leased (unaudited) to 14 tenants at the time of acquisition.

The accompanying statements of revenues and certain expenses have been prepared on the accrual basis of accounting. The statements of revenues and certain expenses have been prepared for the purpose of complying with the provisions of Article 3-14 of Regulation S-X promulgated by the Securities and Exchange Commission and for inclusion in this Current Report on Form 8-K/A of Terreno Realty Corporation and are not intended to be a complete presentation of the revenues and expenses of the Property for the period from January 1, 2012 to April 30, 2012 and for the year ended December 31, 2011 as certain expenses, primarily depreciation and amortization expense and other costs not comparable to the proposed future operations of the Property have been excluded. Management is not aware of any material factors at the Property other than those disclosed above, that would cause the reported financial information not to be necessarily indicative of future operating results.

Revenue Recognition

Rental revenues from operating leases are recorded on a straight-line basis over the term of the leases. Tenant reimbursements represent recoveries from tenants for utilities and certain property maintenance expenses. Tenant reimbursements are recognized as revenues in the period the applicable costs are accrued.

Property Operating Expenses

Property operating expenses represent the direct expenses of operating the Property and include maintenance, utilities, property management fees, repairs, and insurance costs that are expected to continue in the ongoing operations of the Property. Expenditures for maintenance and repairs are charged to operations as incurred.

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Use of Estimates

The preparation of the statements of revenues and certain expenses in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions of the reported amounts of revenues and certain expenses during the reporting period. Actual results could differ from those estimates used in the preparation of the statements of revenues and certain expenses.

Interim Statements

The statement of revenues and certain expenses for the period from January 1, 2012 to April 30, 2012 is unaudited, however, in the opinion of management of Terreno Realty Corporation, all significant adjustments necessary for a fair presentation of the statement for the interim period have been included. The results of operations for the interim period are not necessarily indicative of the results to be expected for the full year of the operation of the Property.

Tenant Concentration

For the year ended December 31, 2011, two tenants accounted for approximately 29% of rental revenues.

Future Minimum Rental Income

Future minimum rents to be received under non-cancelable lease agreements as of December 31, 2011 were as follows (in thousands):

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Report of Independent Auditor

The Board of Directors and Stockholders of

Terreno Realty Corporation

San Francisco, California

We have audited the accompanying statement of revenues and certain expenses of Caribbean (the “Property”) for the year ended December 31, 2011. This statement of revenues and certain expenses is the responsibility of the Company’s management. Our responsibility is to express an opinion on this statement based on our audit.

We conducted our audit in accordance with auditing standards generally accepted in the United States. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the statement of revenues and certain expenses is free of material misstatement. We were not engaged to perform an audit of the Property’s internal control over financial reporting. Our audit included consideration of internal control over financial reporting as a basis for designing audit procedures that are appropriate in the circumstances, but not for the purpose of expressing an opinion on the effectiveness of the Property’s internal control over financial reporting. Accordingly, we express no such opinion. An audit also includes assessing the basis of accounting used and significant estimates made by management, as well as evaluating the overall statement presentation. We believe that our audit provides a reasonable basis for our opinion.

The accompanying statement of revenues and certain expenses of the Property was prepared for the purpose of complying with the rules and regulations of the Securities and Exchange Commission for inclusion in the Form 8-K/A of Terreno Realty Corporation as described in Note 1, and is not intended to be a complete presentation of the Property’s revenues and expenses.

In our opinion, the statement of revenues and certain expenses referred to above presents fairly, in all material respects, the revenues and certain expenses described in Note 1 of Caribbean for the year ended December 31, 2011, in conformity with U.S. generally accepted accounting principles.

/s/ Ernst & Young LLP

San Francisco, California

July 27, 2012

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Caribbean

Statements of Revenues and Certain Expenses

For the Period from January 1, 2012 to May 31, 2012 (unaudited)

and the Year Ended December 31, 2011

(in thousands)

See accompanying notes to statements of revenues and certain expenses.

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Caribbean

Notes to Statements of Revenues and Certain Expenses

For the Period from January 1, 2012 to May 31, 2012 (unaudited)

and the Year Ended December 31, 2011

The accompanying statements of revenues and certain expenses present the results of operations of Caribbean (the “Property”) for the period from January 1, 2012 to May 31, 2012 and the year ended December 31, 2011. The Property was acquired by a wholly-owned subsidiary of Terreno Realty Corporation from a third-party seller, Arden Realty Limited Partnership, on July 3, 2012 for approximately $33.7 million. The Property is located in Sunnyvale, California and consists of three multi-tenant industrial buildings containing 171,707 square feet (unaudited), which were 100% leased (unaudited) to 2 tenants at the time of acquisition.

The accompanying statements of revenues and certain expenses have been prepared on the accrual basis of accounting. The statements of revenues and certain expenses have been prepared for the purpose of complying with the provisions of Article 3-14 of Regulation S-X promulgated by the Securities and Exchange Commission and for inclusion in this Current Report on Form 8-K/A of Terreno Realty Corporation and are not intended to be a complete presentation of the revenues and expenses of the Property for the period from January 1, 2012 to May 31, 2012 and for the year ended December 31, 2011 as certain expenses, primarily depreciation and amortization expense and other costs not comparable to the proposed future operations of the Property have been excluded. Management is not aware of any material factors at the Property other than those disclosed above, that would cause the reported financial information not to be necessarily indicative of future operating results.

Revenue Recognition

Rental revenues from operating leases are recorded on a straight-line basis over the term of the leases. Tenant reimbursements represent recoveries from tenants for utilities and certain property maintenance expenses. Tenant reimbursements are recognized as revenues in the period the applicable costs are accrued.

Property Operating Expenses

Property operating expenses represent the direct expenses of operating the Property and include maintenance, utilities, property management fees, repairs, and insurance costs that are expected to continue in the ongoing operations of the Property. Expenditures for maintenance and repairs are charged to operations as incurred.

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Use of Estimates

The preparation of the statements of revenues and certain expenses in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions of the reported amounts of revenues and certain expenses during the reporting period. Actual results could differ from those estimates used in the preparation of the statements of revenues and certain expenses.

Interim Statements

The statement of revenues and certain expenses for the period from January 1, 2012 to May 31, 2012 is unaudited, however, in the opinion of management of Terreno Realty Corporation, all significant adjustments necessary for a fair presentation of the statement for the interim period have been included. The results of operations for the interim period are not necessarily indicative of the results to be expected for the full year of the operation of the Property.

Tenant Concentration

For the year ended December 31, 2011, one tenants accounted for approximately 79% of rental revenues.

Future Minimum Rental Income

Future minimum rents to be received under non-cancelable lease agreements as of December 31, 2011 were as follows (in thousands):

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UNAUDITED PRO FORMA FINANCIAL INFORMATION OF TERRENO REALTY

CORPORATION

Terreno Realty Corporation (the “Company”) commenced operations with the completion of its initial public offering (“IPO”) of 8,750,000 shares of common stock and a concurrent private placement of an aggregate of 350,000 shares of common stock to its executive officers at a price per share of $20.00 on February 16, 2010. The net proceeds of the IPO and concurrent private placement were approximately $169.8 million after deducting the full underwriting discount of approximately $10.5 million and other offering expenses of approximately $1.7 million. On January 13, 2012, the Company completed a public follow-on offering of 4,000,000 shares of common stock at a price per share of $14.25. On February 13, 2012, the Company sold an additional 61,853 shares of common stock at a price per share of $14.25 upon the exercise by underwriters of their option to purchase additional shares. The net proceeds of the offering, after deducting the underwriting discount and offering expenses, were approximately $54.7 million.

On July 19, 2012, the Company completed an offering of 1,840,000 shares of 7.75% Series A Cumulative Redeemable Preferred Stock (the “Series A Preferred Stock), including the sale of 240,000 shares upon the exercise by the underwriters of their option to purchase additional shares, at a price per share of $25.00. The estimated net proceeds of the preferred offering, after deducting the underwriting discount and estimated offering expenses, were approximately $44.3 million.

The unaudited pro forma condensed consolidated balance sheet as of March 31, 2012 is based on the Company’s consolidated balance sheet and reflects the acquisition of Garfield and Caribbean, as well as the preferred stock offering, as if such transactions had occurred on March 31, 2012. The unaudited pro forma condensed consolidated statements of operations for the three months ended March 31, 2012 and for the year ended December 31, 2011 have been prepared to reflect the incremental effect of the acquisition of properties by the Company during the period from January 1, 2012 to July 3, 2012 (the “2012 Acquisitions”) and the preferred stock offering on July 19, 2012 as if such transactions had occurred on January 1, 2011. The following table summarizes the 2012 Acquisitions:

The unaudited pro forma financial information is not necessarily indicative of what the Company’s results of operations or financial condition would have been assuming the acquisition of properties had occurred at the beginning of the periods presented, nor is it indicative of the Company’s results of operations or financial condition for future periods. In management’s opinion, all adjustments necessary to reflect the effects of these transactions have been made. The unaudited pro forma financial information and accompanying notes should be read in conjunction with the Company’s financial statements included on Form 10-K for the year ended December 31, 2011 and Quarterly Report on Form 10-Q for the three months ended March 31, 2012.

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Terreno Realty Corporation

Pro Forma Condensed Consolidated Balance Sheet

As of March 31, 2012

(in thousands – except share and per share data)

(Unaudited)

See accompanying notes to unaudited pro forma condensed consolidated balance sheet.

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Terreno Realty Corporation

Notes to Pro Forma Condensed Consolidated Balance Sheet

As of March 31, 2012

(Unaudited)

13

Terreno Realty Corporation

Pro Forma Condensed Consolidated Statement of Operations

For the Three Months Ended March 31, 2012

(in thousands – except share and per share data)

(Unaudited)

See accompanying notes to unaudited pro forma condensed consolidated statement of operations.

14

Terreno Realty Corporation

Notes to Pro Forma Condensed Consolidated Statement of Operations

For the Three Months Ended March 31, 2012

(Unaudited)

15

Terreno Realty Corporation

Pro Forma Condensed Consolidated Statement of Operations

For Year Ended December 31, 2011

(in thousands – except share and per share data)

(Unaudited)

See accompanying notes to unaudited pro forma condensed consolidated statement of operations.

16

Terreno Realty Corporation

Notes to Pro Forma Condensed Consolidated Statement of Operations

For the Year Ended December 31, 2011

(Unaudited)

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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 hereunto duly authorized.

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Exhibit Index

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