Green-Naghdi's theory of generalized thermoelasticity is applied to study the reflection of P and SV waves from the free surface of a magneto-thermoelastic solid half-space. The boundary conditions are satisfied by appropriate potential functions to obtain a system of four non-homogeneous equations in reflection coefficients. The reflection coefficients depend upon the angle of incidence of P and SV waves, magnetic field, thermal field, diffusion parameters and other material constants. The numerical values of the modulus of the reflection coefficients are shown graphically with the angle of incidence of P and SV waves. The effect of magnetic field is observed significantly on various reflected waves.