This classroom-based study investigated the antecedents of epistemic curiosity among 25 Thai university students in an English oral communication course. Using a whole-class survey and focus group interview, we recursively asked the students to describe a time in class when they experienced epistemic curiosity and the reasons behind it. A modified version of constant comparative analysis suggested seven thematic factors as the antecedents of epistemic curiosity and positive affect linked to its experience. Utilizing descriptions of the lessons kept in the teacher's record, we provide contextualized accounts of how and why the students experienced epistemic curiosity in class. We conclude by offering pedagogical suggestions for creating learning environments that inspire language learners' epistemic curiosity.