Can leaders benefit from vocalizing uncertainty? Past research outlines two opposing positions. On one hand, individuals who express confidence signal competence and, as a result, attain greater influence in social groups. On the other hand, research on leader humility, authenticity, and self-disclosure suggests that leaders who express vulnerability, not conviction, achieve greater social influence. In this work, we attempt to reconcile these competing positions by considering two additional hypotheses. First, expressing uncertainty may be beneficial in moderate doses, but detrimental in especially small or large doses. Second, followers’ intolerance of uncertainty (i.e., “need for closure”) may be a critical moderator of the relationship between leader-expressed uncertainty and social influence. We conducted five experimental studies to determine whether the link between expressed uncertainty and leader influence may be negative, positive, curvilinear (i.e., inverse U-shaped), and/or moderated by follower’s tolerance of uncertainty. We find overwhelming evidence that the link between expressed uncertainty and leader influence is negative. Leaders who express uncertainty are perceived as less effective, less warm, and less competent. Beyond these subjective evaluations, leader-expressed uncertainty has behavioral consequences, reducing advice-taking, leader selection, and reward allocation. We find no evidence of positive, curvilinear, or interaction effects.