The United States and France signed the Treaty of Alliance on February 6, 1778.
The agreement was concluded in Paris during the American Revolutionary War. It followed the Treaty of Amity and Commerce, which established commercial relations and formal French recognition of the United States. Together, the treaties marked a major diplomatic breakthrough for the American cause.
The alliance was defensive: France promised military support if Britain attacked because of the new relationship, while the United States agreed not to make a separate peace with Britain. French money, supplies, troops, and naval power later became crucial to the American war effort.
News of the American victory at Saratoga helped encourage France to move from covert assistance to open alliance. The treaty is sometimes confused with the 1783 Treaty of Paris, which ended the war and recognized American independence. The alliance instead addressed wartime cooperation and French support for the United States.