Background <p>Peer teaching through online discussion forums (ODFs) has the potential to engage and meet the needs of novice and experienced anatomy learners in the medical and health professions. Exploring ODF engagement patterns of learners with and without anatomy coursework can generate insights to effectively support students with different learning needs.</p> Purpose <p>To explore cognitive levels of engagement and social participatory learning roles of students with and without anatomy coursework when using student-led ODFs.</p> Method <p>This is a mixed-methods study of first-year occupational therapy students who engaged in peer learning on anatomy ODFs. A descriptive qualitative approach was used to conduct directed content analysis of the text-based posts of seven anatomy ODFs. Posts were categorized into social participatory learning roles and Bloom’s cognitive level of learning. Engagement patterns were defined as frequency of posts and cognitive level represented.</p> Findings <p>Of 96 students included in the study, 67 (70%) had anatomy coursework. The proportion of students who contributed to the ODFs (<i>X</i>² (1, <i>n</i> = 96) = 0.03, <i>p</i> = 0.54) and their engagement did not differ between groups (Mann–Whitney <i>U</i> = 753.50, <i>p</i> = 0.08). The ODF posts of students with previous anatomy coursework were more often classified as information providers (<i>n</i> = 120 posts, 47%), while the posts by students without anatomy coursework were most frequently initiators (<i>n</i> = 76 posts, 44%).</p> Conclusion <p>Students with and without anatomy backgrounds contributed to ODFs using a similar level of engagement but different social participatory roles. This work highlights the importance of supporting different peer-learning roles in anatomy ODFs.</p>