The 4th Air Group (第四航空隊 Dai Yon Kōkūtai) was a land-based bomber aircraft unit of the Imperial Japanese Navy Air Service (IJNAS) during the Pacific campaign of World War II. The unit was formed on 10 February 1942 and flew the Mitsubishi G4M Rikko Navy Type 1 Attack Bomber aircraft. That same month, the 4th Naval Air Group (NAG) deployed to Rabaul, New Britain and supported Japanese operations during the early stages of the New Guinea Campaign, first as part of the 24th Air Flotilla and from April as part of the 25th Air Flotilla. The newly arrived unit took heavy losses on 20 February during an action off Bougainville, losing 15 of 17 bombers sent to attack a United States Navy aircraft carrier task force.