This research explored competing predictions for the relation between uncertainty and interpersonal attraction. Two studies investigated whether uncertainty regarding another person's interest is associated with an increase or decrease in attraction. Study 1 revealed that when participants evaluated people whose expressed attraction was either certain or uncertain, participants experienced more liking for those who were associated with certainty. In Study 2, compared to a control condition, uncertainty produced more attraction but the greater attraction was mediated by a desire to reduce uncertainty. We conclude by proposing an explanation for why different research paradigms have produced different conclusions regarding uncertainty and the situations necessary for uncertainty to produce interpersonal attraction.