A phenomenological mean-field theory is presented for the kinetics of strain relaxation due to misfit dislocation generation in the strained-layer growth of epitaxial semiconductor films on thin compliant substrates. The theory provides a generalized dislocation kinetic framework by coupling the mechanics of an epitaxial film on a compliant substrate with a well-known description of plastic deformation dynamics in semiconductor crystals. The theoretical results reproduce successfully recent experimental data for strain relaxation in the InAs/GaAs(110) heteroepitaxial system. ©1998 American Institute of Physics.