This study estimates the effect of professorial tenure on undergraduate ratings of learning, instructor quality, and course quality at the University of California, San Diego from Summer 2004 to Spring 2012. During this eight-year period, 120 assistant professors received tenure and 83 associate professors attained full rank. A differences-in-differences model controlling for teaching experience, study hours, response rate, and unobserved heterogeneity among terms, courses, and professors suggests that for a given professor, tenure does not have a significant impact on student ratings of teaching performance, at least in the immediate years after advancement. The results are similar for the promotion from associate to full professor.