Professional development on inquiry-based learning (IBL) generally draws heavily on the principle of providing instruction in line with what teachers are expected to do in their classroom. So far, however, relatively little is known about how this impacts teachers' educational beliefs, even though these beliefs ultimately determine their classroom behavior. The present study therefore investigates how immersion in inquiry-based learning affects student teachers' beliefs about knowledge goals, in addition to their self-efficacy for inquiry. In total, 302 student history teachers participated in a 4-h long inquiry activity designed within the WISE learning environment, and completed a pre- and posttest right before and after the intervention. Multilevel analyses suggest that the intervention had a significant positive effect on the value that student teachers attributed to procedural knowledge goals, or learning how historical knowledge is constructed, and on student teachers' self-efficacy for conducting inquiries. Despite these general positive results, however, the results also show that the impact of the intervention differed significantly across students. In particular, it appears that immersion in IBL had little effect on a subgroup of 25 student-teachers, who held largely content-oriented beliefs. Based on these findings, the present study discusses a number of implications for professional development on IBL.