| Country: | BEL |
| Maint: | the Roads and Traffic Agency of the Brussels-Capital Region, Flemish government and Walloon Government |
| Type: | A |
| Route: | 3 |
| Map: | Snelweg_A3_Belgie.png |
| Length Km: | 134 |
| Direction A: | West |
| Terminus A: | in Brussels |
| Junction: | 19 Evere 20 Kraainem Sint.-Stevens-Woluwe junction 21 Steenokkerzeel/Sterrebeek 22 Tervuren Leuven junction 23 Haasrode-Blanden/Waver 24 Boutersem 25 Tienen 26 Jodoigne/Orp-Jauche 27 Huy/Lincent 28 Hannuit/St-Truiden 28a Geer 29 Waremme 30 St-Georges-s/M 31 Loncin junction 32 Alleur 33 Rocourt/Tongres Vottem junction 34 Hermée 35 Oupeye Cheratte junction 36 Blégny 37 Herve Battice junction 37bis Thimister-Clermont unnumbered 38 Eupen/Welkenraedt 39 Aachen-Süd/Eynatten 40 Lichtenbusch |
| Direction B: | East |
| Terminus B: | at German border near Aachen |
The A3 is a Belgian motorway (mainly classified as the E40) extending from the east of Brussels (Boulevard Reyers), through Leuven, onwards to Liège. Just past the ring of Liège, the motorway continues to Verviers, Eupen and the German border.
The section between Liège (intersection of Hauts-Sarts) and the German border is part of the King Baudouin Motorway (Baldwin König Autobahn in German and Koning Boudewijnsnelweg in Dutch). Crossing the Hesbaye (French) or Haspengouw (Dutch), the Walloon section between Leuven and Liège is named the Hesbignonne.