The Advanced Placement (AP) program is widely offered in American high schools and has been touted as a way to close racial and socioeconomic gaps in educational outcomes. Using administrative data from Michigan, I exploit variation within high schools across time in AP course offerings to identify the relationship between AP course availability, AP participation, and postsecondary outcomes. I find that students from non economically disadvantaged families, white and Asian students, and higher-achieving students are more likely to take advantage of additional AP courses when they are offered, thus widening existing gaps in course-taking. I find little evidence that additional AP availability is related to improved college outcomes for any students, with the exception of the most academically prepared students. Expanding access to AP courses without additional incentives or support for disadvantaged students to succeed is unlikely to address educational inequality. [This is the online version of an article published in "Education Finance and Policy."]