The Martin XB-33 was a bomber project submitted to the USAAF in March of 1941 for an improved version of the B-26 Marauder powered by a pair of Wright R-3350 air-cooled radials. By May 8, 1941, it had been redesigned with four 1800 hp Wright R-2600-15 radials with a wing mounted high on the fuaelage and twin tails. The crew was to have been seven, and a gross weight of 95,000 was projected. The bombload was to have been 12,000 pounds, and an armament of eight 0.50-inch machine guns was to have been carried. The high-winged aircraft was to have had a wingspan of 134 feet 0 inches and the length was to have been 79 feet 10 inches.
Two prototypes were ordered under the designation XB-33A, and on January 17, 1942 an order for 402 B-33As was placed. The production of the B-33 was to have been carried out at a new government-owned plant at Omaha, Nebraska that would be operated by Martin. However, the entire B-33 project was cancelled on November 25, 1942 so that Martin-Omaha could concentrate on the manufacture of the B-29 Superfortress.