Addressing conventional reinforced concrete (RC) shear walls’ susceptibility to brittle failure and residual deformation during earthquakes; this study investigates carbon fiber reinforced polymer (CFRP)-RC composites for enhanced seismic resilience. CFRP’s superior strength-to-weight ratio; corrosion resistance; and self-centering potential address post-earthquake reparability challenges. Current knowledge gaps persist in size-effect mechanisms under combined geometric and reinforcement parameters (shear span ratio; horizontal reinforcement ratio; height-to-thickness ratio). Numerical analysis of 28 models evaluates hysteretic behavior; strength degradation patterns; ductility coefficients; and residual deformation characteristics. A refined size-effect model incorporating CFRP’s strain distribution overcomes existing predictive limitations; advancing performance-based design of damage-tolerant structures.