While survey data supports a strong relationship between personality and labor market outcomes, the exact mechanisms behind this association remain unexplored. In this paper, we take advantage of a controlled laboratory set-up to explore whether this relationship operates through productivity. Using a real-e ort task, we analyse the impact of the Big Five personality traits on performance. We nd that more neurotic subjects perform worse, and that more conscientious individuals perform better. These ndings are in line with previous survey studies and suggest that at least part of the e ect of personality on labor market outcomes operates through individual productivity. In addition, we nd evidence that gender and university major a ect the impact of the Big Five personality traits on performance.