Omus dejeani is a species of flightless tiger beetle (Cicindelidae) that is found from British Columbia almost to northern California in dense, coastal forests. It is the largest species of the genus, at between 15-20 mm. The genus Omus is placed within the tribe Omini, and is considered the most primitive of the tiger beetles. Omus is placed in Omini with the North American genera Amblycheila and the African Platychile.