The Bajau or Bajaw ( /ˈbædʒɔː/ or /ˈbɑːdʒaʊ/), also spelled Bajao, Badjau, Badjaw, or Badjao, are an indigenous ethnic group of Maritime Southeast Asia. Bajau continue to live a seaborne lifestyle, making use of small wooden sailing vessels (such as the perahu and vinta).

Due to escalated conflicts in their native Sulu Archipelago, and discrimination in the Philippines with regards to education and employment, most of the Bajau have migrated to neighboring Malaysia over the course of 50 years. Currently they are the second largest ethnic group in the state of Sabah, making up 13.4% of the total population. Groups of Bajau have also migrated to Sulawesi and Kalimantan in Indonesia, although figures of their exact population are unknown.

Bajau have sometimes been referred to as the Sea Gypsies, although the term has been used to encompass a number of non-related ethnic groups with similar traditional lifestyles, such as the Moken of the Burmese-Thai Mergui Archipelago and the Orang Laut of southeastern Sumatra and the Riau Islands of Indonesia. The modern outward spread of the Bajau from older inhabited areas seems to have been associated with the development of sea trade in sea cucumber (trepang).