Questioning as one of the most important pedagogical tools has been extensively attended to in formal teaching environments, but few studies have shed light on questioning in more informal contexts such as museums. This study sought to understand how museum educators' questioning may open up spaces for students to engage and participate in instructional discourses. To this end, we analyzed the questions museum educators asked during field trips to an industrial history museum, noting their number, type, and the extent to which they may invite student participation. The findings showed that the museum educators employed a majority of closed questions, which mainly allowed for one-word answers from a small number of students, and used few open questions to provide opportunities for extended participation by a larger number of students. The findings have implications for museum curriculum design and museum educator training, in which the ramifications of question asking should be taken into account.