Parnas may refer to:
- David Parnas (born 1941), pioneer of software engineering who developed the concept of module design which is the foundation of object-oriented programming today
- Jakub Karol Parnas (1884–1949), Polish biochemist
- Parnas, Saint Petersburg, historical region of Saint Petersburg
- Parnas, Saint Petersburg Metro, metro station in Saint Petersburg
- Parnas Railway Station, railway station in Saint Petersburg
- People's Freedom Party (abbreviated as PARNAS), an opposition political party in Russia
- Mount Parnassus, mountain in central Greece
- Mount Sutro (former name Parnassus), hill in San Francisco, California
- Parnassus, New Zealand, town in New Zealand
- Parnassos (municipality), municipality in Greece