Abstract <p>This research examines the effect of the impedance parameter on the behavior of different reflected wave types at the stress-free surface of a porous generalized thermoelastic half-space. The governing equations are initially derived in a two-dimensional framework and then transformed into their non-dimensional form. Thereafter, potential functions are employed to further simplification of the system. A normal mode technique is used to obtain the solution. The investigation demonstrates the presence of coupled waves, namely longitudinal wave (P-Wave), thermal wave (T-Wave), porous wave (PS-Wave) and independent transverse wave (SV-Wave), which are affected by thermal and porous effects. The amplitude ratios of the reflected waves are obtained by applying appropriate boundary conditions at the interface. The analysis demonstrates that these ratios are significantly sensitivity to the angle of incident, frequency, and impedance parameters. The effect of impedance parameters is presented as amplitude ratios for a specific model. The conclusion highlights key findings and their implications. Comparative analysis with established models in specific cases demonstrates strong agreement, thereby reinforcing the validity of the present model.</p>