The main emphasis of the present study is to analyze the MHD stagnation point flow of a Williamson nanofluid over a unsteady stretching sheet with convective boundary conditions and non-uniform heat source/sink. Using suitable similarity transformations the governing partial differential equations were transformed into coupled nonlinear ordinary differential equations with. These equations were then solved by numerical technique known as Runge-Kutta-Felhberg 45 order method. Obtained numerical solutions are presented in the form of graphs and tables for different values of flow pertinent parameters such as; magnetic parameter(M), Prandtl number (Pr), velocity ratio parameter ( ), Williamson parameter (W), Lewis number (Le), Unsteadiness parameter (A), Brownian motion parameter (Nb), thermophoresis parameter (Nt), Biot number (δ) and non-uniform heat source/sink (A*, B*). Numerical results are obtained for velocity, temperature and concentration, as well as the skin friction coefficient, local Nusselt number and local Sherwood number.