Linear, nonlinear, and total refractive index changes are investigated theoretically in asymmetric coupled quantum wells. The analytical expressions for the linear and third-order nonlinear refractive index changes are obtained based on the density matrix method and the iterative approach. Numerical calculations are performed for typical GaAs/Al(subscript x)Ga(subscript 1-x)As asymmetric coupled quantum wells. The calculated results reveal that a large variation of the refractive index near the transition energy can be obtained in asymmetric coupled quantum wells, and that the incident optical intensity and the structure parameters, such as the barrier width and the right-well width, have great effects on the total refractive index changes.