The U.S. military artillery designation system was changed in 1962, redesignating the 105mm M2A1 howitzer the M101A1. The gun continued to see service in the Korean and Vietnam Wars. Though a similar model, the M102 howitzer, shared the same roles in battle, it never fully replaced the M101A1. Today, the M101A1 has been retired by the U.S. military, though it continues to see service with many other countries.
By the end of the Second World War, 8,536 105 mm towed howitzers had been built and post-war production continued at Rock Island Arsenal until 1953, by which time 10,202 had been built.
The Canadian Forces continued to use the M2A1 as the C2 Howitzer until 1997, when a modification was made to extend its service life; it is now designated the C3. The changes include a longer barrel, a muzzle brake, reinforced trails and the removal of shield flaps. It remains the standard light howitzer of Canadian Forces Reserve units. The C3 is used by Reserve units in Glacier National Park in British Columbia as a means of avalanche control. In addition, the M101 has found a second use in the U.S. as an avalanche control gun, supervised by the US Forest Service.
France and the State of Vietnam used it during the First Indochina War, as did the People's Army of Vietnam, who were supplied with this weapon by China PR along with other captured Kuomintang artillery pieces. Today upgraded M2A1s are still being used by the People's Army of Vietnam. It remains as the primary tactical field howitzer of the VPA.
A number of M2/M101 howitzers were used by the Socialist Federal Republic of Yugoslavia and approximately 50 were inherited by Croatia, of which 4 are still in use for training with the Croatian army.
M2 Howitzers are still in limited service in the Australian Army Reserve, but are being replaced with 81mm mortars with an emphasis on the retention of indirect fire support skills. In regular service they were replaced by the 105mm L119 Hamel gun and the 155mm M198 howitzers.
Two M2 howitzers (1942) are still employed in providing the gun salute at Kristiansten Fortress, in Trondheim, Norway. M101/M2 is one of three approved salute guns in the Norwegian armed forces, and have been reduced to a caliber of 75 mm for this purpose. They are used for gun salute also at Rena and Setermoen.