Humor is a popular tool used by instructors to engage students. However, some instructor jokes may be perceived as less funny and more offensive by particular groups of students. Previous studies have shown that student gender impacts student perception of instructor humor; however, to our knowledge no studies have explored whether there are differences in how other identity groups interpret instructor humor. In this study, we surveyed 1,637 students across 25 different college science courses at a research-intensive institution in the Southwest United States. Students evaluated a set of topics that science instructors might joke about in class as to whether they were funny and offensive. Using binary logistic regression, we analyzed whether students of different identities, including race/ethnicity, political affiliation, LGBTQ+ status, religious affiliation, and native language, differentially perceived joke topics to be funny and offensive if told by an instructor in class. We identified that topics which tended to be perceived by students as funny rather than offensive were generally less likely to be perceived as funny to non-native English language speakers compared with native English speakers. We also found that students were more likely to be offended by jokes about their own identity group. This work identifies potentially humorous topics that instructors should avoid because they could be offensive to groups of students. This study also highlights topics that tend to be perceived as funny to most students, which indicates that instructors who joke about such topics may be universally benefitting college science students.