RS3 or RS-3 may refer to:
Vehicles Automobiles Audi RS3, a 2011–present German compact performance car Baojun RS-3, a 2019–present Chinese subcompact SUV
Other RS3 (sail), a windsurfing sail ALCO RS-3, diesel locomotive built by American Locomotive Company and Montreal Locomotive Works Aprilia RS Cube, also known as the RS3, a 2002–2004 Italian MotoGP race bike
Video games Racing Simulation 3, a 2002 racing video game Romancing SaGa 3, a 1995 role-playing video game RuneScape 3, a 2013 fantasy massively multiplayer online role-playing video game
Other uses Resistant starch RS3, a prebiotic starch formed when starch-containing foods are cooked and cooled