To refrain from cheating, students need to adopt an array of discipline-specific standards of academic integrity. The high rates of cheating in college show evidence that many undergraduates fall short of these standards. Little research has examined how instructors teach academic integrity, leaving gaps in our knowledge about how academic integrity develops. To examine how instructors teach academic integrity, this article reports on two studies of college courses. Researchers attended lectures and collected course materials for classes in the social sciences (N = 56, Study 1) and engineering (N = 5, Study 2) and coded all content for discussions of cheating. Instructors rarely discussed or defined academic integrity. Explanations of why students should avoid cheating were infrequent and typically referenced punishment. Consequently, many students misremembered class academic integrity policies. This research suggests that many students do not receive the instruction needed to learn academic integrity.