A key form of student-level accountability is the requirement for students to pass high school exit exams (HSEEs) in order to receive a diploma. In this paper, we examine the impact of HSEEs on dropout during a period when these exams became more common and rigorous. Further, we study whether offering alternate pathways to graduation for students who cannot pass HSEEs moderates any dropout effects. Using a district-grade-level panel assembled from the Common Core of Data, we exploit the fact that new exit exam policies first affect a particular graduating class, so we can isolate the impact of exposure to HSEEs for students in one grade in a district separate from other unaffected grades in the same district. We estimate dropout effects by grade for all students, and by race, sex, and urbanicity. We find that HSEEs increase dropout rates for students in the 12th grade, with especially large effects for African-American students. Dropout effects are uniformly larger in states that do not provide alternate pathways to receive a diploma or alternative credentials for students that cannot pass exit exams. We estimate that 1.25 percent of 12th graders in these states do not graduate with their high school class, likely due to having a diploma withheld because of inability to pass the requisite HSEE. (Contains 21 footnotes, 7 tables and 3 figures.)