Breadnut is an indigenous fruit commonly found in Southeast Asia. The authors recognized the potential of breadnut as a food source; thus, the study was set out to determine the proximate composition and antioxidant activity of breadnut seed flour. The sample was found to contain 75% carbohydrates, 9.07% fat, and 6.16% protein. Moreover, the flour made from breadnut yielded a DPPH scavenging activity of 97.33%, an indication of high antioxidant capacity. The flour was blended with wheat flour to investigate its functional properties. It was observed that the 50:50 breadnut seed flour and wheat flour showed potential in terms of water absorption capacity, fat absorption capacity, emulsion capacity, and foaming ability. With the rising population and threat to food and nutrition security, alternative sources must be explored. This study illustrated the potential of breadnut as a source of energy and other nutrients. More so, its functional behavior as an alternative or at least composite to wheat flour.