This study considers natural convection heat transfer in a permeable cavity using ternary nanoparticles. The primary objective of adopting ternary nanoparticles is to enhance the thermal conductivity of a regular base fluid. It is also examined how thermal radiation and heat generation affect the thermal performance of a fluid in a cavity. The proposed model is solved using the finite difference method, and simulations are conducted using MATLAB software. It is observed that the heat transfer in a cavity can be enhanced by replacing the conventional fluid with ternary nanofluid. Furthermore, the amount of heat transferred is relatively low when the right wall is maintained at a constant temperature (ϵ=0); however, it increases when ϵ>0.