Citizens' Military Training Camps (CMTC) were military training programs of the United States. Held annually each summer during the years 1921 to 1940, the CMTC camps differed from National Guard and Organized Reserve training in that the program allowed male citizens to obtain basic military training without an obligation to call-up for active duty. The CMTC were authorized by the National Defense Act of 1920 as a compromise that rejected universal military training. In its nearly two decades of operation, the CMTC trained some 400,000 men in at least one season from 1921 to 1940. Overall the program was disappointing, as only 5,000 officer commissions were awarded to men who completed the required four summers of training.
Before the United States entered World War I, private citizens of the Preparedness Movement set up what were known as the "Plattsburg camps" to build a reserve of qualified men. These provided at least one summer of training in 1915 and 1916 to some 40,000 men, who were all college graduates and largely drawn from elite social classes.