Help seeking is a self-regulated learning strategy, and peer help is an important form of interaction in online education. Yet, students often do not seek help even at the cost of lower performance. To understand the factors behind online students' commitment to peer help, this study implemented a peer-help discussion forum in an online course and investigated the relationship among students' help-seeking profiles, epistemic beliefs (EB), and their actual participation in peer help. The findings revealed a significant relationship between students' EB and the number of response posts in the peer-help forum. Moreover, EB moderated the relationship between students' help-seeking profiles and the number of response posts. Theoretical and practical implications are drawn from the findings.