Young boys have undergone military training since ancient times. Egypt, Assyria, Rome and Greece all maintained large armies when war was mostly hand-to-hand combat. Boys underwent rigorous physical training and learned to fight with swords and other weapons.

In medieval Europe, the sons of nobles were squired to other noble families to be given private training in knighthood and battle. Another tradition at that time was for noblemen to purchase commissions from the king and become high-ranking officers without any special training or schooling. Royalty supported this system because it ensured them a supply of officers who would support their regimes at no cost to the crown.

There are a few scant records of military schools in 17th Century Europe, and some may have been operating even earlier than that. However, there are records from the 18th and 19th centuries of military schools that educated the sons of noble families. These national schools received government funding and were run in conjunction with national armies. After the French Revolution, European armies became bigger and more complex to supervise, and national military schools filled the need for specialized officer training.

Sons of noble families entered military training at young ages. For example, Manfred von Richthofen, the famous "Red Baron" flying ace of World War 1, was only eleven years old when his family enrolled him at the Wahlstatt Royal Military Academy, where one of his classmates was eleven-year-old Crown Prince Frederick Karl. Most of these academies are no longer in operation. There are a few exceptions, such as École Spéciale Militaire de Saint-Cyr, the foremost military school of France, and The Royal Military Academy Sandhurst, the training center for British officers.

The United States is unique in that its military schools for boys never received public funds and are privately owned and operated. The Continental Congress debated setting up such schools, but in the end, agreed only to fund the United States Military Academy at West Point. West Point opened in 1802 during Thomas Jefferson's presidency.

In the early 19th century, military schools were very much in vogue in the USA. Some remain in operation from that period and maintain their long traditions of training boys for careers as military officers. However, many military schools gained the reputation of being private reform schools for wayward sons of wealthy families.

During the VietNam era, military life went out of style. Progressive views dominated the field of education, as schools adapted changes such as open classrooms, more student participation and freedom, student-designed curricula, fewer lectures, and so forth. Over 450 military schools did not survive this era. They either closed or became traditional boarding or day schools. Many adapted progressive ideas such as co-ed classes and more liberal arts studies.

Today a few outstanding college-preparatory military academies are still in operation. They have highly selective admissions processes and superior academics. Other military schools remain in business by advertising themselves as places that instill discipline and structure in the lives of troubled teens, although they do not offer such teens counseling, substance-abuse treatment, physician-supervised care and medications, or other therapeutic interventions.