The Japan Air Self-Defense Force (Japanese: 航空自衛隊, Hepburn: Kōkū Jieitai), JASDF (空自, Kūji), also referred to as the Japanese Air Force, is the air and space branch of the Japan Self-Defense Forces, responsible for the defense of Japanese airspace, other air and space operations, cyberwarfare and electronic warfare. The JASDF carries out combat air patrols around Japan, while also maintaining a network of ground and air early-warning radar systems. The branch also has an aerobatic team known as Blue Impulse and has provided air transport in UN peacekeeping missions.

The JASDF had an estimated 49,913 personnel as of 2018, and as of 2023 operates about 712 aircraft, approximately 321 of them being fighter aircraft.

The service will be renamed in 2027 to the Japan Air and Space Self-Defense Force (航空宇宙自衛隊, Kōkū Uchū Jieitai), in recognition of the increasing importance of the space domain.

Japan did not have a separate air force before and during World War II. Aviation operations were carried out by the Imperial Japanese Army Air Service and the Imperial Japanese Navy Air Service (Kōkūtai). Following defeat in World War II, the Imperial Japanese Army and Navy (including their respective Air Services) were disbanded in 1945.^{[citation needed]}

Under the supervision of the United States occupation authorities, a pacifist Japanese government was appointed in place of the militaristic governments that administered the Empire of Japan during the war.^{[citation needed]} The new government drafted a postwar constitution. While the primary intent of this endeavor was to place the country's political structure on a firmly democratic footing, the constitution endorsed by the United States and ratified by the Diet of Japan in 1947 also contained Article 9 which strictly prohibited Japan from having a regular military.^{[citation needed]}

The U.S. occupation formally ended in 1952, although a large American garrison remained in Japan, to defend the country. The victory of the Chinese Communist Party in the Chinese Civil War and the onset of the Korean War led the Americans to reconsider what role the Japanese could be expected to play in, at the very least, defending their own home islands against growing Chinese, Soviet and North Korean power in the region. Under U.S. guidance, on 1 July 1954 the National Security Board was reorganized as the Defense Agency, and the National Security Force was reorganized afterwards as the Japan Ground Self-Defense Force (de facto post-war Japanese Army), the Coastal Safety Force was reorganized as the Japan Maritime Self-Defense Force (de facto post-war Japanese Navy) and the Japan Air Self-Defense Force (de facto post-war Japanese Air Force) was established as a new branch of JSDF. General Keizō Hayashi was appointed as the first Chairman of Joint Staff Council—professional head of the three branches. The enabling legislation for this was the 1954 Self-Defense Forces Act (Act No. 165 of 1954).

The Far East Air Force, U.S. Air Force, announced on 6 January 1955, that 85 aircraft would be turned over to the fledgling Japanese air force on about 15 January, the first equipment of the new force.

The JASDF Air Defense Command (Japan) [ja] Headquarters was relocated from Fuchu Air Base to Yokota Air Base on March 26, 2012. The relocation is due to the 2002 Defense Policy Review Initiative. The purpose is to strengthen the U.S.-Japan Security Alliance. The ADC Headquarters does command and control operations to defend Japanese airspace.^{[citation needed]}