In a companion paper, shear strength models for reinforced concrete (RC) slender beams and deep beams were developed, addressing the transition of shear failure mechanism according to the shear span-to-depth ratio (a/d). In the present study, by integrating these two shear strength models, a unified shear strength model was developed that was applicable to both slender beams and deep beams with and without shear reinforcement. The proposed model was verified by comparisons with existing experimental results. The comparisons showed that, for a wide range of values of design parameters, the proposed model predicts the shear strength of concrete beams better than current design methods. For convenience in design practice, a simplified design equation was developed.