Deformation can refer to:
- Deformation (engineering), when an object is changed temporarily (elastic deformation) or permanently (plastic deformation or fracture) due to applied force.
- Deformation (mechanics), A more in—depth article that describes deformation as the displacement of a continuum body
- Deformation (meteorology), important in the formation of atmospheric fronts
- Deformation theory, in mathematics
- Deformity, in medicine, a major difference in the shape of body part or organ compared to the average shape of that part
- Deformation (science), a change in the volume and/or shape of the Earth's crust.