Two similar-sized scops-owl species, the Elegant Scops-Owl (Otus elegans) and the Japanese Scops-Owl (O. semitorques) occur syntopically in a forest on Okinawa Island, Japan. We investigated diets of these owls to evaluate the breadth of their food niches and examine potential mechanisms that might differentiate their food niches. Elegant Scops-Owls fed predominantly on orthopterans, whereas Japanese Scops-Owls took prey from many taxonomic groups. Although we observed dietary overlap, food niches were differentiated by prey size and habitat. Elegant Scops-Owls mostly foraged on arboreal prey, whereas Japanese Scops-Owls took both arboreal and terrestrial prey. Elegant Scops-Owls specialized on small prey, whereas Japanese Scops-Owls preyed equally on small- to large-sized prey. Foraging habitat of these owls may reflect differences in prey locomotion, and differences in prey sizes may correspond to body-size differences between the two species. Food-niche differences may relax competition between these species.