The Andaman Sea is a body of water to the southeast of the Bay of Bengal, south of Myanmar, west of Thailand and east of the Andaman Islands; it is part of the Indian Ocean. It is roughly 1,200 kilometres (750 mi) long (north-south) and 650 kilometres (400 mi) wide (east-west), with an area of 797,700 square kilometres (308,000 sq mi). Its average depth is 870 metres (2,854 ft), and the maximum depth is 3,777 metres (12,392 ft).

At its southeastern reaches, the Andaman Sea narrows to form the Straits of Malacca, which separate the Malay Peninsula from the island of Sumatra.