A mathematical model is presented to analyze the unsteady boundary layer slip flow with Soret effect and chemical reaction over a permeable vertical plate. The dimensionless governing equations are solved analytically by using the perturbation technique. The effects of various flow parameters of the velocity, temperature, and concentration fields are presented graphically and discussed in detail. The results obtained show that the velocity, temperature, and concentration are appreciably influenced by the presence of thermal diffusion, chemical reaction, thermal radiation, and magnetic field. Also, the effects of various parameters on the skin friction coefficient, rate of heat transfer, and the rate of mass transfer at the surface are discussed. It is observed that (i) Velocity increases with an increase in Grashof number, solutal Grashof number, and porosity parameter, but it shows the reverse effect in the cases of radiation parameter, magnetic parameter, chemical reaction parameter, and Schmidt number; (ii) Temperature distribution decreases with an increase in Prandtl number, radiation parameter, and heat source parameter; and (iii) Concentration distribution decreases with an increase in Schmidt number, chemical reaction parameter, and Soret number. © 2016 by Begell House, Inc.