OTAN most commonly refers to the French, Portuguese and Spanish acronym of NATO, an intergovernmental military alliance.
Otan or OTAN may refer to:
- Otan, political party of Kazakhstan, formed into Nur Otan in 2006 and into Amanat in 2022
- Otan Ayegbaju, or Otan, a town in Nigeria
- Autan, or Otan, a village in Syria