The present experiment is the first empirical test of the Behaviour Analysis Interview (BAI), an interview technique developed by F. E. Inbau, J. E. Reid, J. P. Buckley, & B. C. Jayne (2001) designed to evoke different verbal and non-verbal responses from liars and truth-tellers. Inbau et al. expect liars to be less helpful than truth-tellers in investigations and to exhibit more nervous behaviours. Just the opposite predictions, however, follow from the deception literature, which notes that liars take their credibility less for granted and are therefore more aware of their responses and their impact on others. This suggests that liars’ answers should be more helpful than truth-tellers’ answers, and liars’ non-verbal responses should appear more relaxed than truth-tellers’ non-verbal responses. In the present experiment, 40 participants (undergraduate students) lied or told the truth about an event during a BAI interview. The interviews were coded according to Inbau et al.'s guidelines. The results showed that, compared to liars, truth-tellers (a) were more naive and evasive when explaining the purpose of the interview, and (b) were less likely to name someone who they felt certain did not commit the crime. Truth-tellers also exhibited more nervous behaviours. The results were consistent with the predictions of the deception literature, and directly opposed to the predictions of BAI.