Examining the experiences of seven preservice teachers enrolled in a materials development class, this qualitative case study aimed to explore the way their participation in the materials development process was connected not only to their increased knowledge of and skills in materials development but also to their self-perceived confidence as prospective teachers, contributing to their professional development. The data were collected from multiple reflection papers and were analyzed qualitatively. The findings demonstrated that the materials development class offered the preservice teachers an opportunity to gain insight into the importance of materials in language education and of teachers being knowledgeable and skilled in materials design and development. They also came to a new realization that teachers were active agents who could take initiatives in adapting and developing materials, rather than passive users following the prescribed textbooks. The materials development class further taught them the need to prioritize the goal of promoting successful language learning when developing materials and to take a critical approach in order to counteract any biased cultural representations and their negative consequences on students’ worldviews. Gaining confidence, the preservice teachers spoke highly of their experiential learning in the class as they thought the experience prepared them to become more competent teachers.