The carabid beetle fauna of Lanai includes nine native Hawaiian species, and four extralimital alien species. The three species of Mecyclothorax Sharp precinctive to Lanai—M. filipes (Sharp), M. mundanus (Sharp), and M. flavipes, new species—are taxonomically revised. Lanai non-native carabid species include Metacolpodes buchanani (Hope) (new island record), Gnathaphanus picipes (MacLeay), G. multipunctatus (MacLeay) (new island record), and Perigona nigriceps (Dejean) (new island record). A key to species of Harpalini introduced to the Hawaiian Islands is provided. Historical records of native Lanai carabid species indicate that they occurred in both summit cloud forest and in riparian corridors of the mesic and dry forest communities. Present-day records indicate restriction of these species solely to the cloud forest zone. The known historical diminution of summit cloud forest establishes a minimum area that has supported persistent populations for several of Lanai's native carabid taxa. Three of the four alien species have been recorded from cloud and mesic forest communities as well as lowland dry forest not known to support native carabid beetles. Currently, native and non-native species exhibit extensive distributional overlap. However, based on fine-scale, field-collection data, this geographic sympatry overstates the extent of ecological interactions between native and non-native taxa. Whereas native species occur in the cloud forest community, non-native species are more broadly distributed in anthropogenically-disturbed situations including the ecologically devastated dry forest community as well as smaller patches of disturbance within the native cloud forest.