The Northrop P-61 Black Widow is a twin-engine United States Army Air Forces fighter aircraft of World War II. It was the first operational U.S. warplane designed specifically as a night fighter.

It was an all-metal, twin-engine, twin-boom design armed with four forward-firing 20 mm (.79 in) Hispano M2 autocannon in the lower fuselage, and four .50 in (12.7 mm) M2 Browning machine guns in a dorsal gun turret. Developed during the war, the first test flight was made on 26 May 1942, with the first production aircraft rolling off the assembly line in October 1943.