Women Marines became a permanent part of the regular Marine Corps on 12 June 1948 when Congress passed the Women's Armed Services Integration Act (Public Law 625), but they had already proved themselves in two world wars.

During World War I, Opha May Johnson was the first of 305 women to be accepted for duty in the Marine Corps Reserve on 13 August 1918. Most women filled clerical billets at Headquarters, Marine Corps to release male Marines qualified for active field service to fight in France. Other women filled jobs at recruiting stations throughout the United States. On 30 July 1919, after the war was over, orders were issued for separation of all women from the Corps.

Twenty-five years later, women were back to "free a man to fight." The Marine Corps Women's Reserve was established in February 1943. Before World War II ended, a total of 23,145 officer and enlisted women reservists served in the Corps. Unlike their predecessors, women Marines in World War II performed over 200 military assignments. In addition to clerical work, their numbers included parachute riggers, mechanics, radio operators, map makers, motor transport support, and welders. By June 1944, women reservists made up 85 percent of the enlisted personnel on duty at Headquarters, Marine Corps and almost two-thirds of the personnel manning all major posts and stations in the United States and Hawaii. Following the surrender of Japan, demobilization of the Women's Reserve proceeded rapidly, but a number of them returned to service as regulars under the 1948 Act.  

In August 1950, for the first time in history, the Women Reserves were mobilized for the Korean War where the number of women Marines on active duty reached a peak strength of 2,787. Like the women of two previous wars, they stepped into stateside jobs and freed male Marines for combat duty. Women continued to serve in an expanding range of billets and by the height of the Vietnam War, there were about 2,700 women Marines on active duty serving both stateside and overseas. During this period, the Marine Corps also began opening up career-type formal training programs to women officers and advanced technical training to enlisted women. By 1975, the Corps approved the assignment of women to all occupational fields except infantry, artillery, armor and pilot/air crew. Approximately 1,000 women Marines were deployed to Southwest Asia for Operations Desert Shield and Desert Storm in 1990-1991.

Milestones for women officers include: Col Margaret A. Brewer was appointed to a general officer's billet with the rank of brigadier general becoming the first woman general officer in the history of the Corps (1978); Col Gail M. Reals became the first woman selected by a board of general officers to be advanced to brigadier general (1985); BGen Carol A. Mutter assumed command of the 3d Force Service Support Group, Okinawa, becoming the first woman to command a Fleet Marine Force unit at the flag level (1992); 2dLt Sarah Deal became the first woman Marine selected for Naval aviation training (1993); BGen Mutter became the first woman major general in the Marine Corps and the senior woman on active duty in the armed services (1994); LtGen Mutter became the first woman Marine and the second woman in the history of the armed services to wear three stars (1996); 1stLt Vernice Armour became the first female African-American combat pilot in the Marine Corps as well as any other U.S. armed service (2002).

Today, women account for 4.3 percent of all Marine officers and women make up 5.1 percent of the active duty enlisted force in the Marine Corps. These numbers continue to grow as do opportunities to serve. Ninety-three percent of all occupational fields and 62 percent of all positions are now open to women. Like their distinguished predecessors, women in the Marine Corps today continue to serve proudly and capably in whatever capacity their country and Corps requires.