Otoyol 3

O-3 shield}}
O-3
European Motorway
Avrupa Otoyolu
Route information
Part of E80
Part of AH1 and AH5
Length245 km (152 mi)
Existed1987–present
Major junctions
West end D.100 near Edirne
Major intersections D.555 near Karamesutlu
O-7 in Mahmutbey, Istanbul
O-2 in Mahmutbey, Istanbul
East end O-1 in Eyüp, Istanbul
Location
CountryTurkey
RegionsMarmara
ProvincesEdirne, Kırklareli, Tekirdağ, Istanbul
Major citiesEdirne, Istanbul
Highway system
O-2 O-4
Mahmutbey Toll Plaza on the O-3

Otoyol 3 (English: Motorway 3), also known as the European Motorway (Turkish: Avrupa Otoyolu) and abbreviated as the O-3 is a 245.1 km (152.3 mi) long otoyol in East Thrace, Turkey. The O-3 runs from Edirne to Istanbul and is the only motorway in Turkey located entirely in Europe. The motorway begins west of Edirne at a junction with the D.100 where it then continues as a beltway passing just north of Edirne. From there, the motorway passes through mostly rural farmland until it enters the Istanbul metropolis near Silivri. The eastern end of the O-3 is at the interchange with the O-1, where the motorway becomes Vatan Caddesi and continues into the historic peninsula of Istanbul as a major boulevard.

The O-3 connects with three other motorways, all in Istanbul; the O-1, O-2 and the O-7; and is a part of the E80, the International E-road network and AH1 of the Asian Highway Network. The motorway has six lanes, three in each direction, except for a 44.6 km (27.7 mi) section between Silivri and Esenyurt.