This research tests the hypothesis that arousal increases self-disclosure. We find that affective arousal increases the amount (study 1) and the severity (study 2) of self-disclosure, and that self-disclosure is also increased by physiological arousal (study 3). We further explore the moderating effect of thought frequency on the arousal-disclosure relationship, finding that often-thought-about thoughts are more likely to be disclosed than less thought-about thoughts. This research has practical importance in terms of understanding when and why people self-disclose personal information, and enriches our understanding of the theoretical relationship between arousal and information sharing.