Machiavellianism and deceptive mating tactics can ruin relationships if they go unnoticed. Previous research has shown that people have interpersonal accuracy, the ability to accurately judge certain qualities in other people. We explored interpersonal accuracy for two new qualities, Machiavellianism and deceptive mating tactics of strangers role-playing videotaped responses to being interviewed for an online dating site. Participants watched video clips of senders talking for a short time and rated the senders’ Machiavellianism and deceptive mating tactics. Interpersonal accuracy in the detection of these characteristics was obtained by comparing the receivers’ average ratings to the self-ratings of the senders. We also explored the impact of receivers’ social skills, Machiavellianism, and gender on interpersonal accuracy in judging Machiavellianism and deceptive mating tactics in others. Implications of these findings for research in interpersonal accuracy and social relationships is discussed.