The purpose of this study was to understand how instructional coaches and teachers perceived the value of instructional coaching, and how instructional coaching behaviors influenced teachers’ sense of efficacy. Constructs of instructional leadership that interact with coaching, and organizational structures of schools that influence collective efficacy beliefs were also examined.The complexity of instructional coaching was explored using a qualitative grounded theory research design. Furthermore, data analysis entailed co-constructing theory grounded in the experiences of study participants (Mitchell, 2014) using the self-efficacy strand of Bandura’s Social Cognitive Theory as a framework (Bandura, 1977). Study participants included teachers who taught in the middle grades in public schools in Massachusetts, and each teacher’s instructional coach. Both interview and survey data were collected from study participants. The survey data served to promote the validity of analyses and conclusions. Four broad themes about how teachers and instructional coaches experienced instructional coaching emerged from data. The first theme was committing to instructional coaching, characterized by instructional coaches' desire to possess and exhibit the desired professional traits, and the willingness to develop and refine the skills and knowledge for providing expert instructional coaching. The second theme was implementing and sustaining instructional coaching, which largely represented the school structures for supporting high-quality instructional coaching, including the role of the principal. The third theme incorporated shared values and traditions, the importance of specific instructional coaching actions, and the highly developed school culture in service of promoting and encouraging an atmosphere of professional growth and collaboration. The fourth theme was influencing immediate actions, behaviors, and habits over time, which highlighted aspects of adults as learners. Study results showed a correlation between the third theme that emerged from the data and the psychological and emotional states as a source of efficacy expectation. The data also revealed that trustworthiness of teachers, administrators, and instructional coaches, and a school context that definitively supports a culture of adults as learners, as the most important elements for successful instructional coaching programs. These findings have implications for high-leverage instructional coaching policy and programs, and teacher self-efficacy theory.