The Mitsubishi G4M (一式陸上攻撃機:Type 1 land-based attack aircraft; Allied reporting name Betty) was a twin-engined, land-based bomber aircraft used by the Imperial Japanese Navy in World War II.

It had exceptional range and high-speed at the time of its introduction. However, it was most known for it notoriously underprotected fuel tanks that earned the name "one-shot lighter" from Allied pilots. This was due to the fact that on many occasions, it was used for low altitude torpedo attacks that greatly diminished its advantages. Its relatively large size made it a large target to shoot and the simple approach vector meant an easy interception. When used for middle to high altitude bombing against a stationary target like a supply depot or an airfield, it was another matter entirely. Using its long range and high speed, it would appear from any direction and be gone before fighters could intercept them. Near the end of the war it was used as a kamikaze platform, and was the carrier aircraft for the Ohka.

Probably the best-known incident involving a G4M during the war was the interception of the aircraft carrying IJN Admiral Isoroku Yamamoto by American P-38 Lightnings on April 17, 1943.