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 "Edirne Batı K1" 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 O-3 ends at the Istanbul Bağcılar Mahmutbey Batı K20 Junction.
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.
