Abstract An analysis is presented to study the effects of viscous dissipation and viscoelastic parameter on MHD natural convection flow of viscoelastic fluid over an accelerating permeable surface with thermal radiation and heat source/sink. The governing differential equations that are highly nonlinear are transformed by similarity variables and solved using Spectral Homotopy Analysis Method (SHAM). The effects of various pertinent parameters on the velocity and temperature profiles as well as the skin friction coefficient and the local Nusselt number are presented graphically and in tabular form. The SHAM results are compared favorably with already established results in literatures. It is found that the magnetic field acts as a retarding force on the velocity profile of the flow but has a propelling effect on the thermal condition of the flow. It was revealed that an increase in thermal radiation parameter of the flow produces significant increase in the thermal condition of the fluid temperature.