What are the reputational consequences of being overconfident? We propose that the channel of confidence expression is one key moderator—that is, whether confidence is expressed verbally or nonverbally. In five experiments, participants saw an overconfident and a cautious target (potential collaborators or advisors). Targets expressed confidence, or lack thereof, verbally or nonverbally. Participants then learned targets’ actual performance. Across studies, overconfidence was advantageous initially—regardless of whether targets expressed confidence verbally or nonverbally. After performance was revealed, overconfident targets who had expressed confidence verbally were now viewed more negatively than cautious targets; however, overconfident targets who had expressed confidence nonverbally were viewed more positively than cautious ones. The one condition wherein nonverbal overconfidence was detrimental was when confidence was clearly tied to a verifiable claim. Results suggest that, compared to verbal statements, nonverbal overconfidence leads to reputational benefits so often because its biased nature typically goes undetected by others.