The deformation of a mirror's optical surface due to a spacial variation of the coefficient of thermal expansion is examined. Four types of variations of the coefficient of thermal expansion are studied. These represent variations which result after typical manufacturing and/or fabrication processes. Equations describing the deformations resulting from the variations in the coefficient of thermal expansion are derived for some of the cases. Deformations due to more complex variations in the coefficient of thermal expansion are developed empirically using data generated by the finite-element method.