The 8 inch (203 mm) M110 self-propelled howitzer is an American self-propelled artillery system consisting of an M115 203 mm howitzer installed on a purpose-built chassis. Before its retirement from US service, it was the largest available self-propelled howitzer in the United States Army's inventory; it continues in service with the armed forces of other countries, to which it was exported. Missions include general support, counter-battery fire, and suppression of enemy air defense systems.

The M115 203 mm howitzer, also known as the M115 8-inch Howitzer, and originally the M1 8-inch Howitzer was a towed heavy howitzer developed by the United States Army and used during World War II, the Korean War, and the Vietnam War. Post-WWII it was also adopted by a number of other nations in Europe, the Middle East, and Asia.