Purpose. We examined whether language proficiency had an impact on lie detection. Methods. We collected video footage of 30 targets who spoke English as their native or second language and who lied or told the truth about a transgression. Undergraduate students (N = 51) then judged the veracity of these 30 clips and indicated how confident they were in their ratings. Results. Participants were more confident when judging native‐language truth‐tellers than second‐language truth‐tellers. In addition, participants were more likely to exhibit a truth‐bias when observing native‐language speakers, whereas they were more likely to exhibit a lie‐bias when viewing second‐language speakers. Conclusions. Given the difficulties and biases associated with second‐language lie detection, further research is needed.