The Third Recruit Training Battalion is led by Lieutenant Colonel John M. Barnett and Sergeant Major John D. Logan. Within 3d RTBn, there are four companies: Co I, Co K, Co L, and Co M. Each company contains an average of six, 60- to 80-recruit platoons.

Third Battalion was initially formed on 7 Aug 1940, and existed throughout World War II until it was deactivated on 18 Jun 1947. The battalion was reformed the following year and was used to train draftees from 2 Aug 1948, to 8 Jan 1949, when it was again disbanded.

In February 1949 the battalion was reactivated and was used exclusively to train women Marines until 7 May 1954, when a separate women's training battalion was formed (Fourth Recruit Training Battalion) and male recruits and instructors from Fourth Recruit Training Battalion were re-designated as the Third Recruit Training Battalion.

On 28 Feb 1955, the battalion was again deactivated, and then reformed on 15 Oct 1955 only to be temporarily closed on 25 Oct 1957. Starting in 1958 through the time of the completion of the Depot's first brick recruit barracks in 1960, the battalion was permanently re-established and served the RTR from that ever-familiar location on Wake Blvd for 51 years. From 2007 through 2009, 3d Battalion reestablished Company Q in order to facilitate the mandated creation of an addition 28,000 Marines. In June 2011, 3d Battalion relocated to a new state-of-the-art-complex, complete with new parade deck, PT field, and consolidated mess hall, from where it continues the tradition of making Marines with "Spirit and Discipline."