Kellogg-Briand Pact, also called the Pact of Paris and, more formally, the Treaty for the Renunciation of War, multilateral treaty signed by 15 nations in Paris on August 27, 1928, and later almost universally ratified. The treaty was sponsored and drafted by U.S. Secretary of State Frank B. Kellogg and Foreign Minister Aristide Briand of France. Kellogg was awarded the 1929 Nobel Peace Prize.

The Kellogg-Briand Pact had its genesis in the international antiwar and disarmament conferences held in the 1920s in the aftermath of World War I. In 1927 Briand suggested that the U.S. and France abolish the possibility of war between them. Kellogg expressed the U.S. desire to cast the proposal in a general treaty among all world powers. As a result of the negotiations that followed, the pact bound its signatories to renounce war as an instrument of national policy and to settle international disputes by peaceful means.

As a practical instrument for preventing war the treaty was totally useless; it failed to halt aggression in the 1930s—by Japan in Manchuria (1931) and by Italy in Ethiopia (1935)—and was thus discredited by the time World War II broke out. In international law, however, the treaty was an important step toward establishing the 20th-century concept of war as an outlaw act by an aggressor state on a victim state—in contrast to the older view that war is a legitimate act of state and the initiation of hostilities is of no concern to neutral nations.