Complexity theory may refer to:
- the study of any complex system
- chaos theory
- Computational complexity theory, a field in theoretical computer science and mathematics dealing with the resources required during computation to solve a given problem
- the theoretical treatment of Kolmogorov complexity of a string studied in algorithmic information theory by identifying the length of the shortest binary program which can output that string
- the application of complexity theory to organizations, which has been influential in strategic management and organizational studies; this area is sometimes referred to as complexity strategy or the study of complex adaptive organizations.
See also
- Systems theory (or systemics or general systems theory), an interdisciplinary field including engineering, biology, and philosophy that incorporates science to study large systems
