The Republic of Singapore Navy (RSN) is the naval branch of the Singapore Armed Forces (SAF), responsible for the defence of Singapore against sea-borne threats and protection of its sea lines of communications. The service was formally established in 1967 and has since undergone a substantial modernisation.

The RSN conducts operations with the Malaysian and Indonesian navies to combat piracy and terrorist threats in the crowded littoral waters of the straits of Malacca and Singapore. It also jointly operates the Fokker 50 maritime patrol aircraft with its counterparts from the Republic of Singapore Air Force to provide air surveillance of the seaward approaches to Singapore, which is one of the busiest sealanes in the world. The RSN has engaged in international anti-piracy operations further abroad, partaking in the multinational Combined Task Force 151 off the Gulf of Aden.

Though numerically small in comparison to its much larger neighbours in terms of tonnage and manpower reserves, the RSN seeks to maintain a qualitative superiority over any adversary through the implementation of new technologies, fostering of alliances with extra-regional navies, and increased reliance on automation and unmanned assets. Bilateral exercises with foreign navies are held regularly.

All commissioned ships of the RSN have the prefix RSS standing for Republic of Singapore Ship.