Many states require prospective principals to pass a licensure exam to obtain an administrative license, but we know little about the potential effects of principal licensure exams on the pool of available principals or whether scores predict later job performance. We investigate the most commonly used exam, the School Leaders Licensure Assessment (SLLA), using 10 years of data on Tennessee test takers. We uncover substantial differences in passage rates by test-taker characteristics. In particular, non-Whites are 12 percentage points less likely than otherwise similar White test takers to attain the required licensure score. Although candidates with higher scores are more likely to be hired as principals, we find little evidence that SLLA scores predict measures of principal job performance, including supervisors' evaluation ratings or teachers' assessments of school leadership from a statewide survey. Our results raise questions about whether conditioning administrative licensure on SLLA passage is consistent with principal workforce diversity goals.