Free convection and entropy generation in an inclined square cavity filled with a porous medium is numerically studied in this research and the effect of a partition on the bottom wall is investigated. The left wall of the enclosure is heated with a sinusoidal function and the right wall is cooled isothermally. Horizontal walls of the enclosure are adiabatic. The governing equations are solved numerically in the porous domain by the control volume approach based on the SIMPLE technique. The numerical procedure has been done over a range of parameters such as Rayleigh number, partition height, partition width, location of partition, and inclination angle. The effects of these parameters on the flow and heat transfer characteristics and the entropy generation are studied. The obtained results indicated that the partition can be used as a control element for heat transfer, fluid flow, and entropy generation.