New Mexico Military Institute (NMMI) is a public military junior college and high school in Roswell, New Mexico. Founded in 1891, NMMI operates under the auspices of the State of New Mexico, under a dedicated Board of Regents that reports to the Governor of New Mexico. Located in downtown Roswell, NMMI enrolls nearly 1,000 cadets at the junior college and high school levels each year. NMMI is the only state-supported military college located in the western United States and has many notable alumni who have served at senior levels in the military and private sector.

The school's two-year Army ROTC Early Commissioning Program (ECP) commissions approximately 30 cadets annually as U.S. Army second lieutenants, and almost 100 cadets each year go to one of the five United States Service academies.

The Cadet Honor Code, which was unanimously voted into place by the Corps of Cadets in 1921, states, "A Cadet Will Not Lie, Cheat, or Steal, Nor Tolerate Those Who Do" and is administered by an honor board of cadets, advised by cadre and staff. The school's athletic teams are the Broncos (junior college) and the Colts (high school), and its colors are scarlet and black.

New Mexico Military Institute was founded by Colonel Robert S. Goss and Captain Joseph C. Lea in 1891, originally as the Goss Military Institute, with an initial enrollment of 38 students. It was recognized by the territorial legislature and renamed NMMI in 1893. While the legislature had recognized the school, it failed to provide funding, and the school was forced to close its doors on "Bad Friday", March 29, 1895. In the winter of 1894–1895 a funding bill was prepared and approved by the legislature. James J. Hagerman donated a 40-acre (16 ha) tract of land which became the current location of the institute. The school reopened in the fall of 1898.

Hundreds of graduates served in World War I and World War II, including Medal of Honor recipient John C. Morgan and hotelier Conrad Hilton of the Hilton Hotels chain.

In 1948, the institute introduced a four-year liberal arts college program but discontinued it in 1956.

The school became fully coeducational in 1977, although some females had attended as non-cadet day students from 1891 to 1898.

In 2013, the institute broke off relations with the alumni association over disagreement about finances. Members of the alumni association claimed that this was an effort by the school to gain access and control of the over $5.2 million in assets of the association. On June 10, 2013, the school filed a lawsuit in Chaves County to take control of the assets of the alumni association. Editorial response to the institute's actions has been generally negative, calling it a "hijacking" of the group and its resources. On April 21, 2015, the Fifth Judicial District Court found that the alumni association had not breached its agreement with NMMI and that NMMI had "improperly terminated" the agreement. The judge required the association to turn over the funds.

The current superintendent, Brigadier General (retired) Voris W. McBurnette, was appointed on June 6, 2024.

The original area of land for the campus was donated to the school by local rancher James J. Hagerman, for whom the main barracks complex is named. The institute's buildings are made in a uniform Gothic Revival style out of buff brick. Its architecture and organization was inspired by the Virginia Military Institute. The campus is a designated area on the National Register of Historic Places.

Cadets are organized into a Corps of Cadets, following the organization of a cavalry regiment with a Headquarters Troop that comprises the Marching Band. The regiment comprises three squadrons consisting of four to five troops each. Cadets are structured into classes, 6th Class (9th grade high school equivalent) through 1st Class (college sophomore). Cadets are all treated on the basis of earned merit. The military boarding school environment is maintained by the cadet leadership, with all academic classes, meals, and military and physical training occurring "on post" (on campus) in a controlled environment. Based on the rank structure of the Virginia Military Institute, cadets start out as New Cadets, also known as RATs (recruits at training). College and high school cadets are RATs for one semester, then the next semester are known as yearlings, and after the one year mark they are called Old Cadets. Cadets also earn Junior or Senior Army ROTC positions outside of the Corps, although starting in the fall of 2022 school year, JROTC ranks and Corps ranks will be integrated. College and High School were separated in the Corps and in two different barracks starting in the fall of 2022 as well, except at the regimental staff level. These factors determine a cadet's privileges and authority and define social interactions at the institute.

The rules of the institute for cadets are codified in the "Blue Book". Minor offenses against these rules may result in simple correction of behavior or disciplinary measures like push-ups. Cadets with excessive demerits may be put on disciplinary probation. Cadets who fail to meet standards of academic performance are put on academic probation. Leaving the campus is generally only authorized on weekends, holidays, and during family visits.

All cadets live "on-post" (on-campus) in one of the two barracks.

The commandant and dean of students is COL Thomas Tate, who leads a group of staff that advises the leaders in the corps of cadets, and is responsible for cadet life at the Institute.

The football team, the Broncos, competes in the Southwest Junior College Football Conference with six Texas schools and one Oklahoma school. They are coached by head coach Kurt Taufa'asau, a former NFL pro, alumnus of the Institute, and the Bronco Team. He won the American Community College Football Coaches Association Coach of the Year in addition to NJCAA Coach of the Year and SWJCFC Coach of the Year. They won the 2021 NJCAA National football championship game, which was broadcast nationwide on CBS. Its other sports compete in the Western Junior College Athletic Conference. Their women's college volleyball team, coached by Shelby Fortchner, also competes in the NJCAA and were national runner-ups in the 2021-2022 season. They also have college golf, tennis, cross country, baseball and basketball teams at the NJCAA level, that compete under the Bronco name.

Their High School sports mascot is the Colts, and they compete in various divisions and districts in the NMAA (New Mexico Activities Association), including football, soccer, volleyball, tennis, swimming and diving, golf, basketball, baseball, cross country, and track and field competing with other New Mexico High Schools in the region.

Athletic facilities include: The newly renovated Cahoon Armory, Stapp Parade Field/Soccer Field, Godfrey Athletic Center, NMMI Ballpark, NMMI Football Field, Gene Hardman Memorial Tennis Courts, the NMMI Golf Course, the Outdoor Fitness Factory, and the Sports Medicine Facility.

The Athletic Director since July 2014 is NMMI COL Jose Barron. He was named the NJCAA Athletic Director of the Year in April 2022.

• Link Abrams, basketball player
• Wilson Alvarez, football player
• Bobby Baldock, United States federal appellate judge (Tenth Circuit Court of Appeals)
• Ernst Bertner, first president of the Texas Medical Center
• Norman E. Brinker, founder of Brinker International
• Nicholas Clinch, mountaineer and lawyer, namesake of Clinch Peak
• Matt Coates, football player
• Charles A. Coulombe, writer and historian
• William "Billy Jack" Cox, attorney, author and political activist
• Bill Daniels, cable television pioneer
• Carlo D'Este, U.S. Army lieutenant colonel, military historian
• Sam Donaldson, news anchor
• Julian Ewell, U.S. Army lieutenant general
• Taylor Force, soldier after whom the Taylor Force Act was named
• William J. Gray, New Mexico House of Representatives member, Senior Vice President of Navajo Refining Company and Holly Corporation
• Conrad Hamilton, football player
• Ira B. Harkey Jr., awarded the 1963 Pulitzer Prize for Editorial Writing
• Joe Hernandez, professional football player
• Conrad Hilton, founder of the Hilton Hotel chain
• Conrad Hilton Jr., socialite
• Paul Horgan, two-time Pulitzer Prize-winning author
• Peter Hurd, artist, painted the presidential portrait of Lyndon B. Johnson
• Jessica Jaymes, pornographic actress
• Victor Lownes, Playboy Clubs executive
• Enock Makonzo, football player for the Edmonton Elks
• John C. Morgan, pilot and Medal of Honor recipient of World War II
• Greg Morris, football player
• Hal Mumme, football coach
• Pat O'Rourke, politician
• Guillermo Padrés Elías, governor of Sonora, Mexico
• Diego Pavia, college football player and current starting quarterback at Vanderbilt
• Anthony Principi, fourth United States Secretary of Veterans Affairs
• Bill Purifoy, football player
• Chuck Roberts, news anchor for CNN Headline News
• Dave Sherer, football player
• Blair Smith, football player
• Joe Smith, football player
• Roger Staubach, football player, member of the Pro Football Hall of Fame
• G. Harry Stine, sci-fi writer, model rocketry pioneer
• Jordan Ta'amu, football player
• Casey Urlacher, football player, brother of Brian Urlacher
• Tim Van Galder, football player
• Edwin Walker, U.S. Army major general
• Frank D. White, governor of Arkansas
• Owen Wilson, actor

• New Mexico Military Institute Summer Camp, Main Building, in Lincoln County, New Mexico
• National Register of Historic Places listings in Chaves County, New Mexico

• Official website