Saint Mary's Tower, also known as the Comino Tower, is a large bastioned watchtower on the island of Comino in Malta. It was built in 1618, the fifth of six Wignacourt towers. The tower was used by the Armed Forces of Malta until 2002, and it is now in the hands of Din l-Art Ħelwa.

Comino is a small island of the Maltese archipelago between the islands of Malta and Gozo in the Mediterranean Sea, measuring 3.5 square kilometres (1.4 sq mi) in area. Named after the cumin seed, the island has a permanent population of only two residents and is part of the municipality of Għajnsielem, in southeastern Gozo, from where one priest and one policeman commute. The island is a bird sanctuary and nature reserve.