Carbohydrate-based fat substitutes are of growing interest, because as well as maintaining the flavour of food without increasing costs, they have health-friendly properties. This study examined the effect of adding peach gum polysaccharide (PGP) on the rheological friction behaviour, structure and sensory properties of skimmed milk. Skimmed milk containing 0.5% PGP showed similar rheological behaviour to full-fat milk, i.e., there was no significant difference in flow rate (n and k) or viscoelasticity (G′, G″ and η∗ at 50 rad s−1; P > 0.05). Similarly, tribological testing showed no significant difference in tribological parameters (the average surface roughness was 2.390 and 2.287, and the root mean square was 2.908 and 2.855, respectively). Electron microscopy showed that PGP stabilised the structure of milk. Skimmed milk containing 0.5% PGP showed a similar creamy mouthfeel to full-fat milk. Therefore, PGP has potential to become a new polysaccharide-based fat substitute.