The M982 Excalibur is a 155 mm extended-range guided artillery shell developed in a collaborative effort between the U.S. Army Research Laboratory (ARL) and the United States Army Armament Research, Development and Engineering Center (ARDEC). The Excalibur was developed and/or manufactured by prime contractor Raytheon Missiles & Defense, BAE Systems AB and other subs and primes in multiple capacities such as Camber Corporation and Huntington Ingalls Industries. It is a GPS and inertial-guided munition capable of being used in close support situations within 75–150 meters (250–490 ft) of friendly troops or in situations where targets might be prohibitively close to civilians to attack with conventional unguided artillery fire. In 2015, the United States planned to procure 7,474 rounds with a FY 2015 total program cost of US$1.9341 billion at an average cost of US$258,777 per unit. By 2016, unit costs were reduced to US$68,000 per round. Versions that add laser-guidance capability and are designed to be fired from naval guns began testing in 2015. By October 2018, over 1,400 rounds had been fired in combat.

155 mm is a NATO-standard artillery shell caliber that is used in many field guns, howitzers, and gun-howitzers. It is defined in AOP-29 part 1 with reference to STANAG 4425.