A series of efficient and low-cost Li/ZnO catalysts were prepared by a simple impregnation method and investigated for the synthesis of glycerol carbonate (GC) from the transesterification of glycerol with dimethyl carbonate (DMC). The Li/ZnO catalysts were characterized using XRD, SEM, FT-IR, TG-DSC, TPD and XPS. It was found that the basicity of the catalysts highly depended on the Li loading and calcination temperature. The weak and moderate basic sites on the catalyst surfaces originated from the ZnO and Li+ interaction. The strong basic sites were attributed to the substitution of Zn2+ by Li+ in the ZnO lattice, which led to straining of Zn-O bonds and the formation of [Li+ O−] species. It was the strong basic sites rather than the weak and moderate basic sites that catalyzed the transesterification of glycerol with DMC. The highest catalytic activity was observed over the ZnO loaded with 1wt.% LiNO3 and calcined at 500°C. Glycerol conversion of 97.40% and GC yield of 95.84% were obtained over this catalyst at 95°C in 4h.