In this qualitative and interpretive study, we investigated factors that influenced elementary preservice teachers' self-efficacy in a constructivist, inquiry-based physics class. Bandura's (1977) theory of social learning was used as a basis to examine preservice teacher's self-efficacy. Participants included 70 female EC-4 preservice teachers enrolled in two sections of PHYS 3400. Data collected included individual and focus group interviews, pre and post-concept tests, and participant lesson plans. We present a model showing the impact various factors have on increasing preservice elementary teachers' self efficacy. Results show modeling of (1) grade appropriate science teaching activities, and (2) strategies and participatory experiences in inquiry-based activities were major factors influencing elementary preservice teachers' self-efficacy and outcome expectancy expectations. (Contains 2 figures.)