Critical pedagogy employs dialogue that is embodied, reflective, and authentic with aims to promote action toward social justice. Although online learning is well suited to support several characteristics of critical dialogue (i.e., participant diversity, student discussions, emphasis on reflection), it can also be impersonal and disembodied. The purpose of this paper is to explore the experiences and perceptions of online doctoral students in a course designed to facilitate critical dialogue about education. The course experimented with three discussion formats aimed at achieving critical dialogue: (a) traditional, text-based discussion board; (b) asynchronous video (voice thread), and (c) recorded small-group, synchronous video discussions followed by asynchronous discussion board interactions. In this paper, we share results from student surveys of three semesters of the course (n=22 of 46 students enrolled). The findings suggest that students preferred synchronous video chats and perceived this format as most supportive of critical dialogue. Students, on average, rated the discussion board format as the least enjoyable, least engaging, and least supportive of critical dialogue. Students' open-ended comments emphasized that the discussion board and voice thread formats promoted reflection but were less supportive of interactive dialogue. We conclude by discussing implications regarding course design and student support for online instructors who aim to promote critical dialogue in online courses.