The response of a [0°/90°] composite thermomechanical fatigue (TMF) loading is computed using a completely strain-coupled analysis via the finite element method. Calculations are made for in-phase and out-of-phase TMF conditions assuming either a perfect or an imperfect fiber-matrix interface. In addition, a simplified composites analysis (S-CAN) procedure is used to determine the response assuming no lateral strain coupling between the [0°] and [90°] plies. Comparison of the results from the two analyses indicates that the uncoupled analysis provides accurate strains and fiber stresses in the longitudinal direction, but individual ply (average) stresses are not as well predicted. The complete three-dimensional finite element computations indicate that results obtained using an imperfect interface provide better correlation with experimental data than those obtained assuming perfect bonding. The micromechanical stresses developed at the fiber-matrix interface are used to identify the critical locations where matrix failure is expected to occur. These locations are validated to a reasonable degree with experimental observations.