Online education has the potential to remove barriers and increase access to higher education, but previous studies have revealed mixed results regarding the effect of online enrollment on college students' academic outcomes. This study leverages novel administrative data and a fuzzy regression discontinuity design to examine the impact of online enrollment in introductory STEM coursework on students' probability of STEM success. We find that taking the online version of a required introductory Chemistry course increases students' time-to-degree, with starker increases when focusing on the number of semesters needed to complete a STEM degree.