While heterosexual mismounting between heterospecific Mantodea is occasionally observed in the wild, it does not appear to be a common occurrence, and likely results from misidentifications of pheromone and/or visual cues by mantises. However, accounts of homosexual mismounting between heterospecific male mantises are extremely rare in the literature. The present study provides the first account (to our knowledge) of homosexual mismounting by a male Acromantis japonica Westwood, 1889 on a male Statilia nemoralis Saussure, 1870. This is also as the first formal record of mismounting between Taiwanese mantises in the wild. The possible causes of this rarely observed phenomenon are also discussed.