In current study, the influence of magnetic field (MHD) on heat transfer of natural convection boundary layer flow in Casson ternary hybrid nanofluid past a stretching sheet is studied using numerical simulation. The Newtonian heating boundary conditions that depend on the temperature and velocity terms are taken into this investigation. The particular dimensional governing equations, for the studied problem, are converted to the system of partial differential equations utilizing adequate similarity transformation. Consequently, the system of equations is numerically solved using well-known Kellar box numerical techniques. The obtained numerical results are in excellent approval with previous literature results. The existence of types for composite ternary nanoparticles, which as alumina Al₂O₃, copper oxide CuO, and silver Ag or copper Cu, as well as water H₂O which is considered an essential fluid, are examined. The physical features, such as temperature, velocity, local skin friction coefficient, and local Nusselt number are explored with the variation of MHD Casson ternary hybrid nanofluids parameters and displayed graphically and tabularly in the present study. The numerical outcomes exhibit that when the conjugate parameter values rise, the temperature and local Nusselt number increase, however they decrease as the Casson parameter is reduced.