A method is proposed for the determination of plastic bifurcation buckling load of metal matrix composite plates. The metallic matrix behavior is described by an elastic-viscoplastic constitutive law, while the fibers are assumed to be either elastic or elastic-viscoplastic material. The approach is based on the load level and history dependent instantaneous effective properties of the inelastic plate, which are established by a micromechanical analysis. An incremental procedure is developed in which a buckling condition has to be established and its fulfilment must be checked at each increment. The method is applied for the prediction of the plastic buckling of boron/aluminum composite plates in various situations, by employing the classical and higher order shear deformation plate theories.