The Autoroute 3, abbreviated to A3 or otherwise known as the Dudelange motorway (Luxembourgish: Diddelenger Autobunn, French: Autoroute de Dudelange), is a motorway in southern Luxembourg.

It is 13.318 kilometres (8.275 mi) long and connects Luxembourg City to Dudelange.

At Dudelange, it reaches the French border, whereupon it meets the A31, which leads to Metz.

The A3 was opened in three separate sections: The motorway has two lanes in both directions for its entire length, with the exception of a 1.3 km section on the northbound carriageway, where there are three lanes between the Livange/Bettembourg entry slip road (J2) and the Berchem service station entry slip road, where it again merges to become two lanes.

Media related to A3 (Luxembourg) at Wikimedia Commons