Background/Context Each year, large shares of students who could do well in Advanced Placement courses and exams—known as AP potential students—do not participate, particularly students of color and low-income students. There are a number of prevailing reasons, both structural (schools do not offer the courses, or teachers do not accurately identify students) and as well as student- centered (lack of motivation, conflicts with other activities, or lack of self-efficacy). Purpose/Objective/Research Question/Focus of Study This study seeks to empirically test these common reasons for foregoing AP participation with the following research questions: How are student and school characteristics related to the probabilities of students attending a high school that offers a corresponding course, enrolling in the course, and taking the exam? To what extent are explanations such as students’ constraints on time, lack of motivation, or lack of self-efficacy related to the probability of AP course- and exam-taking, net of student- and school-level measures? How well do AP potential estimates align with teacher recommendations into advanced coursework? We focused on differences across race and class throughout. Research Design We define AP potential as a 60% percent probability or better of receiving at least a 3 on an AP exam in either math or English. Using a nationally representative sample of sophomores in 2002 whom we identified as having AP potential, we answered the first research question with a sequential logit. We then used postestimation commands in Stata to examine motivation, hours working, hours in extracurricular activities, and measures of English and math self-efficacy to address the second research question. For the third research question, we modeled the probability of student misidentification—or the probability that the teacher of a student with AP potential will not identify them for honors or AP courses—using a logit. Conclusions/Recommendations We found that large shares of students did not fulfill their AP potential, which varied by student background and subject area. We did not find support for many of the student-centered reasons for forgoing AP, such as lack of motivation and constraints on time due to work or extra-curricular activities. We did find, however, that teacher identification and academic self-efficacy mattered to AP course- and exam-taking, especially for marginalized students, suggesting viable policy and practice levers to improve equitable AP participation. We discuss implications for policy, practice, and research.