This study investigated the effects of a 1-year professional development (PD) based on a cognitive apprenticeship model of research experiences on inservice teacher self-efficacy of science teaching, motivation, knowledge calibration, and perceptions of inquiry of 19 secondary earth science and biology teachers. The PD facilitator, who serves a dual role as a scientist and teacher educator, utilized a cognitive apprenticeship model to shape both scientific thinking and inquiry instruction with 19 inservice teachers. Results indicated that inservice teachers changed their perceptions of inquiry and maintained high self-efficacy throughout all phases of the study. However, teachers refrained from making long-term changes in their cognitive strategy instruction. Implications provide a fuller picture of teacher learning during a RET program, supported with inquiry instruction and the implications of cognitive apprenticeships in offering authentic science research experiences with minimal laboratory resources.