UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8–K

CURRENT REPORT

Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): November 22, 2012

The Navigators Group, Inc.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (914) 934–8999

(Former name or former address, if changed since last report.)

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:

Item 1.01. Entry Into A Material Definitive Agreement

On November 22, 2012, the Company entered into a $165 million credit facility agreement entitled “Amended and Restated Funds at Lloyd’s Letter of Credit Agreement” with ING Bank, N.V., London Branch, individually and as Administrative Agent and Letter of Credit Agent, JPMorgan Chase Bank, N.A., and Barclays Bank PLC, dated as of November 21, 2012. The credit facility is a letter of credit facility. This new credit facility amended and restated a $165 million letter of credit facility entered into by the parties on March 28, 2011. The credit facility will be used to support the Company’s capacity at its Lloyd’s of London operations for the 2013 and 2014 underwriting years of accounts, as well as prior open years.

The credit facility contains customary covenants for facilities of this type, including restrictions on indebtedness and liens, limitations on mergers, dividends and the sale of assets, and requirements as to maintaining certain consolidated tangible net worth, statutory surplus and other financial ratios. The credit facility also provides for customary events of default, including failure to pay principal, interest or fees when due, failure to comply with covenants, any representation or warranty made by the Company being false in any material respect, default under certain other indebtedness, certain insolvency or receivership events affecting the Company and its subsidiaries, the occurrence of certain material judgments, or a change in control of the Company, and upon an event of default the lenders (subject to the consent of the requisite percentage of the lenders) may immediately terminate their obligations to issue letters of credit, declare the Company’s obligations under the credit facility to become immediately due and payable, and require the Company to deposit in a collateral account collateral with a value equal to 102% of the aggregate face amount of any outstanding letters of credit consisting of cash or other specified collateral including time deposits, certificates of deposit, money market deposits and U.S. government securities subject to varying advance rates. The ability to have letters of credit issued under this facility expires on July 31, 2014. The facility is secured by a pledge of the stock of certain insurance subsidiaries of the Company pursuant to a Security Agreement, dated as of March 28, 2011 and by collateral accounts established in the United States pursuant to the security agreement and in the United Kingdom pursuant to a Deed of Charge dated as of March 28, 2011. One or more of the collateral accounts will be required to be funded upon the occurrence of certain specified events including an event of default, the financial strength rating of the Company falling below A–, the aggregate balance of the letter of credit obligations exceeding the aggregate commitments as a result of a reduction in the aggregate commitments or otherwise, the face amount of the letter of credit exceeding the aggregate commitments as a result of a change in the conversion rate of British pounds into U.S. dollars, the forecast underwriting losses exceeding a certain level for any year supported by a letter of credit, any net unfunded solvency deficit on any open years of account is not funded directly at Lloyd’s within a specified time, or any expiry notice is given with respect to any letter of credit.

Fees payable by the Company under the credit facility include a fee on the daily unused portion of each lender’s letter of credit commitment at the rate of 0.375% and a letter of credit fee with respect to each letter of credit in an amount equal to the applicable letter of credit fee rate. The applicable letter of credit fee rate payable under the credit facility is determined in accordance with the table set forth below based on the Company’s status as determined from its then–current ratings issued by S&P and A.M. Best with respect to the Company’s financial strength rating; provided that if the S&P and A.M. Best ratings are not on the same level, the better rating will apply if they differ by one level, otherwise the lower rating will apply. If at any time the Company does not have both an S&P and A.M. Best rating, then the Company’s status will be determined by the rating that it then has. The applicable letter of credit fee is subject to adjustment in the event of posting of collateral or in the event of a default. As of November 21, 2012, the applicable letter of credit fee rate was 1.35%.

The existing letters of credit which were issued and outstanding under the expired credit facility in an aggregate amount of £96,500,000 issued in British pounds are being replaced by letters of credit to be issued under the new credit facility. The foregoing description of the credit facility is qualified by reference to the full text of the credit facility, which is attached hereto as Exhibit 10.1.

The Administrative Agent and the Lenders under the credit facility and their respective affiliates have various relationships with the Company and its subsidiaries, including the Administrative Agent acting as trustee for the Company’s senior unsecured debt.

Item 2.03. Creation of a Direct Financial Obligation or an Obligation under an Off–Balance Sheet Arrangement

See Item 1.01 above.

Item 9.01. Financial Statements and Exhibits

(d) Exhibits

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.

EXHIBIT INDEX