The present paper is to investigate the effect of initial stress and inclined Load on the plane waves in a linearly micropolar thermoelastic medium possessing cubic symmetry in the context of the threephase-lag-theory. The problem has been solved numerically using the normal mode analysis. Numerical results for the temperature, displacement components, the stresses and microrotation are represented graphically and the results are analyzed. The graphical results indicate that the effect of phase lags, angle of inclination and the initial stress parameter on the plane waves in the micropolar thermoelastic medium are pronounced. The variations of these quantities have been depicted graphically in the three-phase-lag model (3PHL), Lord-Shulman (L-S) theory and Green and Naghdi theory for type III (G-N: III) for an insulated boundary to show the effect of the initial stress and angle of inclination in the medium.