Abstract: A population of the odorous house ant, Tapinoma sessile, was found at an upland site on Maui, Hawaii. Although T. sessile possesses many of the traits shared by most invasive ant species and is a significant urban pest in the continental Usa, this represents the first confirmed record for this species outside its native North American range. Our survey of the site revealed a relatively large (ca. 17 ha) infestation with many closely spaced nests, possibly all belonging to a single supercolony as suggested by the lack of aggression or only occasional non-injurious aggression between workers from distant nests. The odorous house ant is currently abundant at this site, despite the presence of seven other introduced ant species, including the big-headed ant (Pheidole megacephala) and the Argentine ant (Linepithema humile). Based on its behavior at this site, T. sessile may successfully invade other temperate areas in the future, and should be watched for by biosecurity programs.