To evaluate how Advanced Placement (AP) courses affect college-going, we randomly assigned the offer of enrollment into an AP science course to over 1,800 students in twenty-three schools that had not previously offered the course. We find no AP course effects on students' college entrance exam scores (SAT/ACT). As expected, AP course-takers are substantially more likely to take the AP exam than their control group counterparts. At the same time, treatment group students opt out of the exam at very high rates and most do not earn a passing score on the AP exam. Though less precisely estimated, the results also suggest that taking the AP course increases students' aspirations to attend higher-quality colleges but does not lead to enrollment in such institutions.