The effect of WO3 loading on the activity of Pt/WO3/Al2O3 with loadings of 2-20 wt% WO3 in hydrogenolysis of glycerol was investigated. Pt/WO3/Al2O3 with 7wt% WO3 loading (coverage of Al2O3 with WO3 monolayer: ca. 33%) exhibited the highest conversion of glycerol and selectivity to 1,3-propanediol (1,3-PDO). The W-(OH)-Al sites at the boundaries between tungsten oxide monolayer domain and alumina have an important role in the selective hydrogenolysis of glycerol to 1,3-PDO.