Martin Viiask (born April 27, 1983 in Tartu, Estonia) is an Estonian professional basketballer. Viiask started his senior club career in 2000 in Ehitustööriist. In the next year signed with Tartu Ülikool/Rock and played there until 2007, when he signed with Estonian rival BC Kalev/Cramo. He has also played for TTÜ KK and Kuremaa SK. Currently he is back with Tartu Ülikool/Rock. He has also been a member of the Estonia national basketball team.