Modeling of the valence band discontinuity was proposed using Harrison model modified by introducing the effective bond length for AlX (X=P, As, Sb). The valence band discontinuity of heterostructures including AlX as constituent, for example, GaAs Al X Ga 1− x As and Al XIn 1− X As Ga yIn 1− y As , was predicted. The predicted values were in good agreement with the experimental values. Prediction of the valence band discontinuity of quarternary alloy (Al XGa 1−X) yIn 1−yP and pentanary alloy (Al XGa 1−X) 1−z In zP yAs 1−y lattice matched to GaAs was also attempted.