This work performs a comparative investigation into Casson-Williamson fluid flow over a heated porous stretchy sheet. The energy and mass transfer equations are modeled by Cattaneo-Christov theory. The governing flow models are altered into an Ordinary Differential Equation (ODE) model through proper transformations. The Homotopy Analysis Method (HAM) scheme is applied to determine the series solutions. The responses of diverse flow variables to fluid speed, fluid warmness, liquid concentration, skin friction coefficient, local Nusselt number, local Sherwood number, local entropy generation number, and Bejan number are analyzed through graphs and charts. It was found that the fluid speed would subside following an increase in values of the magnetic field, porosity, Casson fluid, Williamson fluid, and injection/suction parameters. The fluid warmness is increased due to high-level radiation, convective heating, and heat generation/absorption parameters and it suppresses the previous highs when enriching the convective cooling parameter. The chemical reaction parameter causes an increase in the thickness of the solutal boundary layer. The larger skin friction coefficient occurs in Casson fluid than Williamson fluid. The local entropy generation is attenuated upon increase in the Casson and Williamson parameters and it aggravates when the Biot number rises. The Bejan number is elevated when the Reynolds, Brinkman, and Biot numbers experience an increase. (c) 2022 Sharif University of Technology. All rights reserved.