Singapore maintains an active conscription system in accordance with the regulations set by the Government of Singapore, known as National Service (NS). This requires all qualified male Singaporean citizens and second-generation permanent residents to serve a period of active duty military service in the uniformed services.

Conscription was first instituted in Singapore in 1967 to help build the country's armed forces having just gained its independence two years prior in 1965. The government's rationale was that a strong military is an indispensable guarantor of the country's continued sovereignty, and has since been expanded to involve its police force and civil defence force. Upon enlistment, male citizens and second-generation permanent residents serve two years in active duty as full-time national servicemen (NSFs) in the Singapore Armed Forces (SAF), Singapore Police Force (SPF) or Singapore Civil Defence Force (SCDF), following which they transit to an operationally-ready reservist state as operationally-ready national servicemen (NSmen).

The majority of NSFs serve in the Army. The reasons for this include the larger relative manpower needs of the Army compared to the country's Navy, Air Force, Police Force and Civil Defence Force. Moreover, as compared to the Army, the Air Force and Navy are smaller armed services composed primarily of professional regular servicemen. Additionally, manpower requirements of the Navy and Air Force tend to be more specialised. The statutory age cap for reservist obligations is 40 for warrant officers, specialists and enlistees, and 50 for commissioned officers.