In contrast with studies that have identified why students commit academic offenses, many educators are familiar with the excuse that an accused student did not know the behavior counted as dishonest. Given the variations in policy and the ways collaboration and code sharing occur in professional and hobbyist spaces, this might be plausible. Mismatches between student’s conception of academic honesty and course policy can have major consequences, from being kicked out of programs to being too nervous to study with peers. In this work, we investigate what students understand about academic integrity in computer science courses and if there are differences based on university, country, demographic, or online versus in-person courses. We present a study that surveys undergraduate computer science students (N = 1,011) at three universities (Australia, Canada, and the United States of America). The results show that all three institutions take academic integrity seriously and their students are aware of its importance, but confusion on what is covered under the policies is common. Interestingly, the results also show that course instructors play a huge role as to what students perceive to be a violation of the academic integrity policy at their institution. By understanding student’s perspectives on academic integrity, educators can better develop policies and practices that reduce inadvertent and mistaken violations of academic integrity policies.