Ma Wan Viaduct, Double-deck viaduct in Tsuen Wan District, Hong Kong.

Ma Wan Viaduct is a two-level bridge in Tsuen Wan that spans across water to connect major transportation routes. The structure accommodates vehicle traffic on the upper level and railway lines on the lower level, serving both car and train passengers.

The viaduct opened in 1997 as part of a major infrastructure program for a new airport and transportation network. It marked an important step in connecting Hong Kong's growing transportation system across the water.

The viaduct carries the Tung Chung line and Airport Express of Hong Kong's Mass Transit Railway on its enclosed lower deck, alongside two emergency road lanes. Its upper deck has a dual three-lane carriageway. The lower roadway is used for maintenance and for diverting traffic during high winds.

The viaduct carries Route 8 traffic and MTR trains, so it is closed to pedestrians and cyclists. Drivers heading from Ma Wan to Lantau cannot turn directly onto the viaduct; they must cross the Tsing Ma Bridge and U-turn at the North West Tsing Yi Interchange. The lower deck roadway is used for maintenance and for diverting traffic during high winds.

Because of the upper deck's lane layout, traffic cannot travel directly between Ma Wan and Lantau: vehicles leaving Ma Wan for Lantau must cross the Tsing Ma Bridge and turn back at the North West Tsing Yi Interchange. The viaduct has six spans, one 80 m, four 87 m and one 75 m long, built of post-tensioned concrete.