Within American gender norms is the expectation that women should be modest. We argue that violating this "modesty norm" by boasting about one’s accomplishments causes women to experience uncomfortable situational arousal that leads to lower motivation for and performance on a self-promotion task. We hypothesized that such negative effects could be offset when an external source for their situational arousal was made available. To test hypotheses, 78 women students from a U.S. Northwestern university wrote a scholarship application essay to promote the merits of either the self (modesty norm violated) or another person as a letter of reference (modesty norm not violated). Half were randomly assigned to hear information about a (fake) subliminal noise generator in the room that might cause "discomfort" (misattribution available) and half were told nothing about the generator (normal condition: misattribution not available). Participants rated the task and 44 new naive participants judged how much scholarship money to award each essay. Results confirmed predictions: under normal conditions, violating the modesty norm led to decreased motivation and performance. However, those who violated the modesty norm with a misattribution source reported increased interest, adopted fewer performance-avoidance goals, perceived their own work to be of higher quality, and produced higher quality work. Results suggest that when a situation helps women to escape the discomfort of defying the modesty norm, self-promotion motivation and performance improve. Further implications for enhancing women’s academic and workplace experiences are discussed.