The A3 motorway is a motorway in Serbia which spans approximately 92 kilometers (57 mi) and is part of the European route E70 through Serbia. It crosses the Syrmia region from east to west, starting at Belgrade and ending at the border crossing with Croatia.

Motorways in Serbia are called auto-put, a name which simply means car-road. Roads that are motorways are categorized as state roads of IA category and are marked with one-digit numbers. Motorways in Serbia have three lanes in each direction, signs are white-on-green, and the normal speed limit is 130 km/h (81 mph). They are maintained and operated by the national road operator company JP "Putevi Srbije".