<p>This study explores the fabrication and characterization of MgAgSb thermoelectric composites to optimize performance through nanoparticle engineering and contact material selection. Adjusting the Mg₃Sb₂ to Ag₃Sb nanopowder molar ratio to 2:1 reduced redundant Ag₃Sb phases, which significantly enhancing thermoelectric efficiency. The effects of contact metals, including Al, Ag, and Ni, were evaluated using fabrication methods such as paste application, cold pressing, foil, and sputtering, showing their impact on the Seebeck coefficient. These results highlight the critical role of material composition and contact engineering in advancing thermoelectric materials. This approach provides a cost-effective strategy to improve MgAgSb composites in p-type thermoelectric modules.</p> Graphical abstract <p></p>