Tomoxia bucephala A. Costa (Coleoptera: Mordellidae), a Palearctic tumbling flower beetle native to Europe, Asia, and northernmost Africa, is now known from North America. The first known occurrences were in 2015 in Essex and Union counties, New Jersey, U.S.A. and in 2019 in Passaic County, New Jersey, all in the New York City metropolitan area. An additional collection documents the species in 2016 from Allegheny County, Pennsylvania, in the Pittsburgh metropolitan area. The multiple occurrences, the large distance between those in New Jersey and Pennsylvania, and multiple detections in natural areas indicate T. bucephala is established in North America and apparently invasive. Several morphological features differentiate T. bucephala from the two congeners native to North America, T. inclusa LeConte and T. lineella LeConte, especially coloration patterns of elytral and pronotal vestiture, and coloration of antennae and front legs. This is the first report of a non-native mordellid species established in North America. Tomoxia bucephala does not appear to pose a significant direct economic threat in North America since it feeds in decaying trees. However, T. bucephala occurrences are within the geographic ranges of T. inclusa and T. lineella, and the biology of T. bucephala is similar to these other Tomoxia species. Thus, T. bucephala likely will expand its range within North America, with probable ecological impact on communities of native saproxylic beetles, especially T. lineella and T. inclusa.