The present study examined the roles of teachers, peers, and materials in the environment in supporting children's inquiry processes at a Reggio Emilia-inspired preschool. Reggio Emilia is an educational system originally developed post-WWII in Italy and now has become a pedological approach that influences early childhood education programs all over the world. Seventeen children and their two teachers were observed over 24 days in the spring and/or fall of one calendar year. Forty-one events in four days were coded for children's inquiry processes (i.e. observing and questioning, predicting, evaluating, comparing, and concluding) and how they were guided (i.e. by teachers, peers and/or materials). The activity context (including art, storytelling, gardening, mapping, constructing, and pretend play) in which the inquiry exchange occurred was also examined. Findings revealed that teachers, peers, and classroom materials supported children's advanced inquiry processes. In addition, advanced inquiry processes were utilized across all six activity contexts.