Our study analyzes the impact of the International Baccalaureate Diploma Programme, a college-preparatory educational program designed for higher-achieving students, on high school academic achievement in Chicago Public Schools. We exploit exogenous variation in the offering of the program across schools over time with a difference-in-differences framework. We estimate a positive effect of the program on the probability of obtaining a B average or better in coursework, with most of the effect accruing to performance in mathematics. Most importantly, the program led to a decrease in the likelihood of high school dropout and an increase in the probability of high school graduation.