In this work, a general solution to the field equations of generalized thermoelastic diffusion in a half-space is considered in the context of fractional order theory of thermoelastic diffusion. The bounding surface of the half-space is taken to be traction free and subjected to a time dependent thermal shock while the chemical potential is assumed to be a known function of time. Laplace transform techniques are used. The analytical solution in the transform domain is obtained by using the eigenvalue approach. Numerical results for the temperature, the displacement, the concentration, stress and chemical potential represented graphically.