Czarnik is a Polish surname. Notable people with the surname include:
- Anthony Czarnik, an American scientist and inventor
- Austin Czarnik (born 1992), American professional ice hockey player
- Marcin Czarnik (born 1976), Polish film and theatre actor
- Melissa Czarnik, emcee and poet based in Brooklyn, NY
- Tamarack R. Czarnik, a medical researcher focused on outer space