Exploring students' epistemic views is important as it should help to better understand how they acquire and work with knowledge. This case study investigated how college students' epistemic views relate to their collaborative inquiry activities in an online knowledge-building environment. Findings based on a mixed-method analysis on students' online discourse and open-ended survey questions suggested that students' knowledge-building activities were positively related to the development of their epistemic views. In particular, when students were able to engage in more productive and effective group inquiry activities, they were more likely to develop a more sophisticated epistemic view that was conducive to sustained idea improvement for advancing knowledge. The study has implications for understanding how students’ views on the nature of knowledge creation and the manner in which collaborative inquiry is conducted in an online environment affect each other.