The crystal structure of Ca0.25Cu0.75TiO3 has been studied between 25 and 1000 degreesC using powder neutron diffraction methods. The diffraction data is well described in space group N-3, and there is no indication of any crystallographic phase transition. The preference of the Jahn-Teller active Cu ion for square planar geometry is believed to be a significant factor in the stabilization of the observed structure.