Within academia, men are tenured at higher rates than women are in most quantitative fields, including economics. Researchers have attempted to identify the source of this disparity but find that nearly 30% of the gap remains unexplained even after controlling for family commitments and differences in productivity. Using data from academic economists' CVs, I test whether coauthored and solo-authored publications matter differently for tenure for men and women. While solo-authored papers send a clear signal about one's ability, coauthored papers are noisy in that they do not provide specific information about each contributor's skills. I find that men are tenured at roughly the same rate regardless of whether they coauthor or solo-author. Women, however, suffer a significant penalty when they coauthor. The results hold after controlling for the total number of papers published, quality of papers, field of study, tenure institution, tenure year, and the number of years it took an individual to go up for tenure. The result is most pronounced for women coauthoring with only men and is less pronounced the more women there are on a paper, suggesting that some gender bias is at play. I present a model in which bias enters when workers collaborate and test its predictions in the data.