In the 2015-16 school year, 75 percent of Chicago Public Schools (CPS) ninth-graders opted out of their assigned high school. These students could choose from more than 300 programs at 138 public high schools. Selective enrollment high schools (SEHSs) were among the most high-profile and most sought-out options. SEHSs aim to provide high-achieving students with a challenging academic experience and admit students based on prior academic performance. While many of the SEHSs are consistently ranked as the top schools in Illinois by U.S. News and World Report, criticisms about these schools include concerns that they disproportionately serve affluent students and drain resources from neighborhood schools. This research asks two questions: (1) How does the admission policy in CPS affect the profile of SEHS students in Chicago? and (2) What effects do SEHSs have on students? Results find that applicants tend to prefer the same selective enrollment high schools. CPS uses multiple academic performance metrics and a proxy for students' SES for SEHS admissions, in part to create more diverse selective enrollment high schools. Although the common perception is that SEHSs benefit all students who attend them, the picture is more complicated, particularly for students who live in low-SES neighborhoods.