The West Gate Bridge is a steel, box girder, cable-stayed bridge in Melbourne, Victoria, Australia, spanning the Yarra River just north of its mouth into Port Phillip. It carries the West Gate Freeway and is a vital link between the inner city (CBD) and Melbourne's western suburbs, with the industrial suburbs in the west, and with the city of Geelong 80 kilometres (50 mi) to the south-west. It is part of one of the busiest road corridors in Australia.

The main river span is 336 metres (1,102 ft) in length, and the height above the water is 58 metres (190 ft). The total length of the bridge is 2,582.6 metres (8,473 ft). It is the fifth-longest in Australia, the longest being Melbourne's Bolte Bridge at 5 kilometres (3.1 mi). The West Gate Bridge is twice as long as the Sydney Harbour Bridge and is one of the highest road decks in Australia, clearing the water at 58 metres (190 ft), with the Sydney Harbour Bridge clearing the water at 49 metres (161 ft).

The bridge passes over Westgate Park, a large environmental and recreational reserve created during the bridge's construction, and carries up to 200,000 vehicles per day.