OUI or Oui may refer to:
- Organizationally Unique Identifier, a unique 24-bit string assigned to computer hardware manufacturers
- Operating under the influence of alcohol or drugs, a variant of driving under the influence
- Oui (album), an album by the band The Sea and Cake
- Oui (magazine), a once-popular men's magazine
- Ouï FM, a French radio station
- Oui, Burkina Faso
- Organic Union International, a French association founded in 1987 by André Gernez and Jean-Pierre Willem
- Oracle Universal Installer