High rates of active student responding and opportunities to respond are considered best-practice instructional strategies for learning. Many educators in higher education have shifted from teaching primarily in-person to either a hybrid or an online format over the past decade. The global pandemic hastened further shifts from in-person to online learning for many institutions of higher education. Given this rapid shift to online instruction, it is critical to evaluate evidence-based teaching practices in online formats. Although there is a robust body of literature that supports the effectiveness of embedding opportunities to respond and active student responding during in-person instruction, to date, there is limited research that evaluates the effects of increased opportunities to respond during synchronous online courses in post-secondary settings. Using an alternating treatments design, this study evaluated the effects of two active student response modalities on response accuracy for seventeen students enrolled in a synchronous online graduate course. The results suggest that students performed more accurately on post-lecture queries following conditions that required written active student responses compared to responds cards. Moreover, the accuracy of correct responding maintained across the exams and the cumulative final exam. Limitations and future implications are discussed.