The Martin P6M SeaMaster was an experimental strategic bomber flying boat built by the Glenn L. Martin Company for the United States Navy that almost entered service; production aircraft were built and Navy crews were undergoing operational training, with service entry expected in about six months, when the program was cancelled on 21 August 1959. Envisioned as a strategic nuclear weapon delivery system for the Navy, the SeaMaster was eclipsed by the Polaris submarine-launched ballistic missile (SLBM). Due to the political situation at the Pentagon, the Navy promoted the P6M primarily as a high speed minelayer.

The Glenn L. Martin Company, also known as The Martin Company from 1917 to 1961, was an American aircraft and aerospace manufacturing company founded by aviation pioneer Glenn L. Martin. The Martin Company produced many important aircraft for the defense of the US and allies, especially during World War II and the Cold War. During the 1950s and '60s, the Martin Company moved from the aircraft industry into the guided missile, space exploration, and space utilization industries.