Axis Powers, countries allied with Nazi Germany before or during World War II. The Rome-Berlin Axis, a diplomatic agreement between Hitler and Mussolini, was formed in 1936 and reinforced by the Italian-German military pact of 1939. Japan joined the pact in 1940, and other countries followed: Hungary, Bulgaria, Romania, Slovakia, and Croatia. The Axis Powers were defeated by the Allies (or Allied Powers), led by the United States, Britain, and the Soviet Union.
See also: World War II.