The Montana State University (MSU) Army Reserve Officers' Training Corps (ROTC) is a program in the university's Department of Military Science. Military training at Montana State College (now MSU) first began with 40 cadets in 1896, just three years after the establishment of the college. The 1862 Morill Act stipulated that all male students under 26 at land grant colleges receive two years of military training. William M. Cobleigh, a professor of chemistry and physics, provided the first instruction in Military Science, and in 1897 Lieutenant George P. Ahern became the first professor of Military Science and Tactics at the college.

In 1916, the United States Congress created the ROTC program as part of the National Defense Act. In early 1917, MSU President James M. Hamilton asked the War Department to formally establish a ROTC program at Montana State College. MSC was one of several land grant colleges designated as a Senior ROTC unit host and detailed as a Branch Infantry ROTC unit.

Following the creation of the U.S. Air Force in 1952, the ROTC program expanded opportunities for military students, allowing them to apply for a commission in any combat arms or technical service branch. The 1964 the ROTC Vitalization Act further transformed the ROTC program, making the program voluntary rather than obligatory. It also offered two- and four-year college scholarships to deserving applicants. 1973 brought another significant change when Montana State University first began accepting women into to the program.

Upon graduation from the ROTC program, cadets commission into the military as a Second Lieutenant with the option to serve four years in active duty or eight years in the National Guard or reserves.