Recently, a novel molten salt electrolysisMolten salt electrolysis using a high-densityDensity cathode such as Cu or Sn has been investigated for the reductionReduction of MgO to Mg. In this study, novel molten salt electrolysisMolten salt electrolysis of MgO was developed using a lightweight cathodeLightweight cathode such as Al metal and a graphite anode for the direct production of Mg–Al alloys. MgO was electrolyzed in a MgF2–LiF–CaF2 molten saltMolten salt under an Ar atmosphere at 1053 K, using a cathodic current densityDensity of 0.318 A/cm2 for 4 h at 1053–1133 K. After electrolysisElectrolysis, 13.9–14.2 mass% Mg–Al alloys containing Al3Mg2 and Al (Mg) mixture were obtained, and a current efficiency of 91.6% was achieved at 1053 K. These results demonstrate that the proposed electrolytic processProcess using an Al cathode is effective for the direct production of Mg–Al alloys from MgO.