The logic underlying inclusive STEM high schools (ISHSs) posits that requiring all students to take advanced college preparatory STEM courses while providing student-centered, reform-oriented instruction, ample student supports, and real-world STEM experiences and role models will prepare and inspire students admitted on the basis of STEM interest rather than prior achievement for postsecondary STEM. This study tests that logic model by comparing the high school experiences and achievement of students in ISHSs and comparison schools in North Carolina. After identifying ISHS and non-STEM comparison high schools serving students who were similar in terms of socioeconomic status and academic achievement prior to high school entry, we employed propensity-score weighting and HLM modeling to estimate the impact of attending an ISHS on a set of outcome measures obtained from student surveys and from the state’s longitudinal student data system. Analyses of student survey data found that attending an ISHS raises the likelihood that a student will complete pre-calculus or calculus and chemistry in high school, leads to increased involvement in STEM extracurricular and out-of-class activities, and enhances interest in science careers and aspirations to earn a master’s or higher degree. Analyses of student outcome data from state administrative records revealed a positive impact of inclusive STEM high school attendance on grade point average (GPA) but not on ACT scores.