This study investigates the effect of offering multiple means of representing content, one aspect of Universal Design for Learning (UDL). Students across the full range of the dis/ability spectrum all too often struggle to achieve course success. UDL-based course design promises to help students with disabilities (whether disclosed or not) as well as help all students, but research is needed to verify UDL's specific benefits for student learning outcomes. This study aims to better understand the efficacy of representing course content using multiple means, which is one aspect of UDL pertaining to perception. Data were gathered from over 50 online courses in 14 subjects across the undergraduate curriculum taught with an adaptive learning system at a women's institution. A panel data analysis with almost 200,000 cases of student learning activities investigated the effect of representing content in multiple ways (i.e., text, video, audio, interactive, or mixed content presentation format). When students used multiple modalities, a positive effect was found on student learning measures of knowledge gained within the adaptive system. The results have implications for future UDL-related research, as well as faculty development and curricular design.