Officer Candidates School (United States Marine Corps)

The United States Marine Corps Officer Candidates School (OCS) is a training regiment designed to screen and evaluate potential Marine Corps Officers. Those who successfully complete the period of instruction are commissioned as Second Lieutenants in the United States Marines. Unlike the other United States military services, the majority of Marine Corps officers complete OCS to earn a commission; the exceptions are midshipmen from the United States Naval Academy, limited duty officers and warrant officers, and inter-service transfers. It is located at Marine Corps Base Quantico.

Depending on the course, Officer Candidates go through either a 10-week Officer Candidates Course (OCC) or Platoon Leaders Class (PLC) combined, or two 6-week PLC courses over separate summers, designed primarily to screen and evaluate candidates' physical and mental capabilities to lead Marines by placing them in leadership positions and physically and mentally demanding environments. The second 6-week course only happens after a candidate's junior year of college. The OCC 10-week course is available to those seeking a commission who meet the requirements to become an officer to include already possessing a bachelor's degree. Students are evaluated during 2–3 day garrison command billets at the company, platoon, and squad level, and fire-team level tactical billets during field exercises and Situational Leadership Events.