The Seyhan Viaduct (Turkish: Seyhan Viyadüğü) is a 470-metre-long (1,540 ft) box-girder bridge that carries the O-51 motorway across the Seyhan River in Adana, Turkey.

The bridge is the northernmost crossing of the river before the Seyhan Dam, just upstream.

The Pozant-Adana-İskenderun highway initially included the 1992-completed Seyhan Viaduct.

[2] Once completed, the route was re-designated as the Adana Beltway (O-50) and has recently been re-designated again, after the O-50 was replaced by the O-51 and O-52.