The Neutrality Acts were a series of acts passed by the US Congress in the 1930s (specifically 1935, 1936, 1937, and 1939) in response to the growing threats and wars that led to World War II. They were spurred by the growth in isolationism and non-interventionism in the US following the US joining World War I, and they sought to ensure that the US would not become entangled again in foreign conflicts.

The legacy of the Neutrality Acts is widely regarded as having been generally negative since they made no distinction between aggressor and victim, treated both equally as belligerents, and limited the US government's ability to aid Britain and France against Nazi Germany. The Acts were largely repealed in 1941, in the face of increasing incidents between German submarines and US vessels in the Battle of the Atlantic and the Japanese attack on Pearl Harbor.