The lattice distortions in single‐crystal Si substrates due to stressed surface films were calculated by linear elastic theory. It is shown that the strains are localized directly underneath discontinuities in the films, and these regions are responsible for the enhanced diffracted intensity experimentally observed in x‐ray topographs of the substrate. A simplified theory is presented which is used to semiquantitatively describe the relationship between film stress and thickness, and enhanced diffracted intensity.