Field theory may refer to:

• Field (mathematics), the theory of the algebraic concept of field
• Field theory (physics), a physical theory which employs fields in the physical sense, consisting of three types:
  • Classical field theory, the theory and dynamics of classical fields
  • Quantum field theory, the theory of quantum mechanical fields
  • Statistical field theory, the theory of critical phase transitions
  • Grand unified theory

• Field theory (psychology), a psychological theory which examines patterns of interaction between the individual and his or her environment
• Field theory (sociology), a sociological theory concerning the relationship between social actors and local social orders