Quantum theory may refer to:
Science
- Quantum mechanics, a major field of physics
- Old quantum theory, predating modern quantum mechanics
- Quantum field theory, an area of quantum mechanics that includes:
- Quantum gravity, a field of theoretical physics
- Quantum optics
- Quantum chemistry
- Quantum information
- Quantum Theory: Concepts and Methods, a 1993 book by Asher Peres
Arts and other media
- Quantum Theory (video game), a 2010 video game
- "Quantum Theory", a song on the Jarvis Cocker album Jarvis