Ximenia americana is a wild edible fruit essential for human consumption due to its high nutritional and phytochemical constituents with significant antioxidant activity. The fruit seed has high potential in its mucilage content. The present study aimed at optimization of mucilage extraction from the Ethiopian cultivar of Ximeina americana fruit seed. The response surface methodology based on a central composite rotatable design was used for the optimization of aqueous extraction of mucilage. The extraction temperature (50–80 °C), time (1.5–4 h), and water-to-seed ratio (20:1–40:1 v/w) were identified as the major factors influencing mucilage yield, water holding capacity, and protein content. Water to seed ratio and time showed significant (p < 0.01) interaction effect on yield. Interactions of water to seed ratio with time and temperature had significant effects (p < 0.05) on the protein content. Water holding capacity of the mucilage was significantly (p < 0.05) affected by the interaction between temperature and time. Optimum extraction processing conditions were obtained to be extraction temperature of 65.06 °C, time of 1.5 h and water to seed ratio of 37.62:1 v/w. The response variables at this operating conditions were found to be extraction yield of 17.31 %, water holding capacity of 11.48 g/g and protein content of 1.75 %. The result demonstrated that the X. americana seed mucilage could be used as a new source of additives in the dairy industry as a fat replacer due to its potent water holding capacity.