In 1875, Fyodor Dostoyevsky proposed that an individual’s laughter grants special insight into their character. To evaluate this conjecture, we showed video clips of 89 targets laughing and not laughing to unacquainted independent observers, who recorded their impressions of the targets’ Big Five personality traits. We correlated the observers’ personality impressions with the targets’ personalities, as measured by self-reports and reports by informants who knew the targets. Observers judged targets’ extraversion more accurately and with greater consensus when targets were laughing than when they were not, consistent with Dostoevsky’s conjecture. However, laughing did not improve the accuracy of observers’ judgments of any other traits. Observers also judged targets to be more extraverted, agreeable, conscientious, and open to new experiences when they were laughing than when they were not.