In this study, oil-in-water emulsions made of medium-chain triglycerides (MCT), mucilage from Dioscorea opposita (DOM), and food-grade polysaccharides (guar gum [GG], xanthan gum [XG] and pectin [Pec]) were prepared using high-pressure homogenisation. The droplet size distributions, microstructure, turbidity, interfacial tension, creaming index, and stability of emulsions were investigated and compared with those of DOM, GG, XG and Pec. The results showed that 0.4 wt% food-grade polysaccharides (GG, XG, and Pec) with 2 wt% DOM contributed more to the stability of the emulsion during storage. In particular, low concentrations of pectin and DOM emulsions presented smaller droplet size distribution, in the range of 86.34–111.30 nm. Hence, DOM has synergistic effects with food-grade polysaccharides, which could improve the stability of emulsions, suggesting that mucilage from Dioscorea opposita has good potential for use as a natural emulsifier.