Achan may refer to the below definitions
- Achan means father in Malayalam language.
- Achan means teacher in Thai language.
- Achan, meaning Lord in Sanskrit
- Achan (Nair Subcaste), deriving from this use, is also a surname used by the Nair caste in Kerala (See Paliath Achan)
- Achan (Bible), a person in the Book of Joshua.
- Achan, Syberia, a village in southeastern Siberia.
- Achan (film), a 2011 Malayalam film starring Thilakan.
- Achan is a hereditary title formerly used by the royal family of Palakkad.