The Battle of Groton Heights (also known as the Battle of Fort Griswold, and occasionally called the Fort Griswold massacre) was a battle of the American Revolutionary War fought on September 6, 1781 between a small Connecticut militia force led by Lieutenant Colonel William Ledyard and the more numerous British forces led by Brigadier General Benedict Arnold and Lieutenant Colonel Edmund Eyre.

Lieutenant General Sir Henry Clinton ordered Arnold to raid the port of New London, Connecticut in an unsuccessful attempt to divert General George Washington from marching against Lord Cornwallis's army in Virginia. The raid was a success, but the Connecticut militia stubbornly resisted British attempts to capture Fort Griswold across the Thames River in Groton, Connecticut. New London was burned along with several ships, but many more ships escaped upriver.

Several leaders of the attacking British force were killed or seriously wounded, but the British eventually breached the fort. As the British entered the fort the Americans surrendered, but the British continued firing and killed many of the defenders. However, the high number of British casualties in the overall expedition against Groton and New London led to criticism of Arnold by some of his superiors. The battle was the last major military encounter of the war in the northern United States, preceding and being overshadowed by the decisive Franco-American Siege of Yorktown about six weeks later. At the battle of Yorktown, the Marquis de Lafayette reportedly yelled, "Remember Fort Griswold!" as American and French forces stormed the redoubts.