A few years ago, the COVID-19 pandemic significantly altered how post-secondary students receive their education. The transition from an in-person to an online class format changed how students interact with their instructors and classmates. In this study, we used student participation scores from two core computer science classes across ten in-person and three online quarters at a public research university to analyze whether the shift to primarily asynchronous online learning impacted the gender gap in student participation scores and students’ attitudes towards themselves and their peers. We observed a shift on the online class forum: in in-person classes, males scored higher on average and dominated the top scores, while in online classes, male and female students participated at approximately the same rate classwide. To understand what drove these changes in participation behavior, we analyzed survey responses from over a quarter of the students enrolled in the online classes. While we found that students of both genders tended to compare themselves to their peers less when classes were online, we also found that this trend was much more accentuated for females than males. This data suggests that observed female participation habits in typical in-person classes are not inherent gender differences, but rather, a product of the environment. Therefore, it is critical that the community continues investigating the root causes of these behavioral differences, and experiments with ways to mitigate them in in-person formats.