Glycerol monodecanoate (GMD) is a medium-chain monoacylglycerol that possesses emulsifying and antibacterial properties. The common emulsifiers carboxymethylcellulose and polysorbate-80 have been reported to cause intestinal microbiota dysbiosis and metabolic disturbances. Glycerol monolaurate (GML), another medium-chain monoacylglycerol, is often used as an emulsifier and could improve metabolism by regulating the gut microbiota. However, research on the effects of GMD on the metabolism and gut microbiota remains scarce. Mice were fed a normal chow diet with or without GMD (150, 800, and 1600 mg kg-1) for 22 weeks. Metabolism indicators and related genes, gut microbiota, and fecal SCFAs were analyzed. The results demonstrated that GMD significantly improved insulin sensitivity, reduced the serum LPS level, and decreased pro-inflammation cytokines including IL-1β, tumor necrosis factor (TNF), and monocyte chemotactic protein 1 (MCP-1). Additionally, 150 and 1600 mg kg-1 GMD could significantly lower the blood glucose content. 1600 mg kg-1 GMD improved cholesterol metabolism and related gene expression compared to 150 and 800 mg kg-1 GMD. Moreover, 150 and 800 mg kg-1 GMD up-regulated the abundance of Lactobacillus and Turicibacter, while 1600 mg kg-1 GMD significantly up-regulated the abundance of Bifidobacterium. Our findings indicated that different doses of GMD had inconsistent effects on lipid metabolism by differentially altering the gut microbiota composition. Meanwhile, all doses of GMD showed excellent effects on increasing insulin sensitivity and improving inflammation.