Südost Autobahn

{{Short description|Motorway in Austria}}

{{Expand German|topic=transp}}{{Infobox road

|country=AUT

|type=A

|route=3

|map=Karte A3 AT.svg

|length_km=38

|terminus_a ={{jct|country=AUT|A|2}}

|junction={{jct|country=AUT|S|31}} near Eisenstadt

|terminus_b=Eisenstadt

{{jct|country=HUN|M|85}} border with {{HUN}}

|regions=Lower Austria, Burgenland

|cities=Eisenstadt

|previous_type=A

|previous_route=2

|next_type=A

|next_route=4

}}

The Südost Autobahn (A3; 'Southeast Motorway') is a motorway, or ‘Autobahn’, in Austria. It runs from the Süd Autobahn at the junction Knoten Guntramsdorf southeast to Eisenstadt.

It was built between the 1970s and 1996, with multiple sections being opened for traffic once at a time.

Near Eisenstadt the A3 ends, where it crosses the Burgenland Expressway S 31 and merges into the B 16. Motorists can proceed on the B 16 towards the border with Hungary and enter the M85 expressway (Hungary) at Sopron. Plans to link the A3 and the M85 directly at the border have been abandoned by the Austrian authorities due to environmental and climate concerns.{{Cite web|title=Südostautobahn A3 im Burgenland wird nicht verlängert|url=https://www.derstandard.at/story/2000128797802/suedostautobahn-a3-im-burgenland-wird-nicht-verlaengert|access-date=2021-08-10|website=DER STANDARD|language=de-AT}}