Coalition headed by Germany, Italy, and Japan that opposed the Allied Powers in World War II. The alliance originated in a series of agreements between Germany and Italy, followed in 1936 by the Rome-Berlin Axis declaration and the German-Japanese Anti-Comintern Pact .
The connection was strengthened by the formal Pact of Steel (1939) between Germany and Italy and by the Tripartite Pact signed by all three powers in 1940. Several other countries, including Hungary, Romania, Bulgaria, Croatia, and Slovakia, later allied themselves with the original Axis Powers.