The Barbaros Boulevard (Turkish: Barbaros Bulvarı) is a 3.1 km (1.9 mi)-long major street in the Beşiktaş disrict on the European Side of Istanbul, Turkey. It runs in a straight line in south-north direction from Beşiktaş Square over Yıldız up to Zincirlikuyu, where it passes over to Büyükdere Avenue. It is named after the Ottoman admiral of the fleet Hayreddin Barbarossa (Turkish: Barbaros Hayrettin Paşa) (c. 1478-1546), whose tomb is located in Beşiktaş.
The 1.5 km (0.93 mi) long boulevard ascends a slope from 1.5 m (4.9 ft) elevation at Beşiktaş Square up to 135 m (443 ft) at Balmumcu before Zincirlikuyu. This part of the street is 50 m (160 ft) wide with a slope gradient of 8%, while the part between Balmumcu and Zincirlikuyu has a width of 30 m (98 ft) and a slope gradient of 2-3%.