The Sentosa Monorail was a monorail system which served as the main means of transportation on the island of Sentosa in Singapore, and has been replaced by the new monorail system, the Sentosa Express. The system was constructed at a cost of S$14 million by Von Roll of Switzerland, who also built the Singapore Cable Car.

Sentosa Island, known mononymously as Sentosa, is an island located off the southern coast of Singapore's main island. The island is separated from the main island of Singapore by a channel of water, the Keppel Harbour, and is adjacent to Pulau Brani, a smaller island wedged between Sentosa and the main island.