When calculating class rank, high schools often give additional weight to grades earned in College Board Advanced Placement (AP) courses as an incentive for students to take hard courses. This paper examines changes in student course-taking behavior after an increase in AP grade weights at Texas high schools. We find that raising the magnitude of the AP grade weight in schools already using weights has a small impact that is limited to white students who are not eligible for free or reduced-price lunch (FRPL). When schools introduce grade weights for the first time, the impact is large and widespread with the probability of taking an AP course increasing by 3 to 12 percent and the number of AP courses taken increasing by 0.13 to 0.95 standard deviations. Impacts are largest among students who are not FRPL eligible.