This study investigated the relationship between a collaborative inquiry teacher professional group (Mills Teacher Scholars (MTS)) and participating teachers' sense of their efficacy in teaching. My mixed methodology used a modified version of the Teacher Sense of Efficacy Scale (TSES, Tschannen-Moran & Woolfolk Hoy, 2001) and background variables to identify patterns in Teacher Scholars' sense of efficacy in teaching. Additionally, I gathered and analyzed teaching narratives of success and struggle from five Teacher Scholars using Narrative Interview techniques (Jovchelovitch, 2000). I found that Teacher Scholars' sense of teaching efficacy in instruction had a positive relationship with their years of experience in teaching, in combination with years of experience in MTS (R2 = 0.097). Patterns emerged from Teacher Scholars' narratives: Teacher Scholars frame success as students learning "despite initial challenges", as a result of teacher intervention. Their narratives of failure involve challenges outside the realm of classroom instruction (often issues of school resources or logistical, routine demands). Teacher Scholars value learning---they name their own learning as a key element of success, and as result of navigating challenge. I found that Teacher Scholars told similar story forms for both narratives of success and narratives of challenge. This "inquiry journey" or" productive struggle" story form begins with challenge, highlights teacher interventions, and ends with reflection on learning. This pattern of narratively transforming frustration to success (at learning) via tinkering and reflection may be one mechanism by which MTS promotes efficacy development in Teacher Scholars. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]