This study addresses the effects of unsteady MHD radiative slip flow of Williamson fluid due to the chemically reacting sheet with variable conductivity and heat source or sink. The boundary layer equations of the Williamson fluid model for heat and mass transfer are deliberated. The governing partial differential equations are transformed into a set of coupled ordinary differential equations of motion for Williamson fluid are modeled under the sheet and then solved numerically by the shooting technique with BVP4C package. The physical features of the model are presented and discussed in graphs and tables. © Springer Nature Switzerland AG 2019.