Oba or OBA may refer to:
- Oba (ruler), an African ruler or king
- Oba (goddess), in Yoruba mythology
- Oba, an island in the North Maluku province of Indonesia
- Oba-Igbomina, a town in Nigeria
- Office Business Applications, software which uses applications within the Microsoft Office system
- Oklahoma Bankers Association, a trade association in Oklahoma, U.S.
- Oklahoma Bar Association, the state bar (legal association) of Oklahoma, U.S.
- On base average, in baseball statistics
- One Bermuda Alliance, a Bermuda political party
- Openbare Bibliotheek Amsterdam, the public library of Amsterdam
- Optical Brightening Agent, a type of dye used in fabric and paper
- Out-of-band agreement, in communications
- Output-based aid, a type of aid to support the delivery of public services in developing countries
- Oxygen Breathing Apparatus, an oxygen supply system used by the US Navy for firefighting
- Orange Beach, Alabama, OBA - Orange Beach Alabama
- OBA, Oxford Business Alumni
- A Japanese name for Perilla