Principals that work with instructional coaches need to understand the conditions necessary to maximize their impact on teacher effectiveness. With any school improvement initiative, the positive presence and explicit support provided by the principal is critical to its overall success (Leithwood & Riehl, 2003; Leithwood et al, 2008; Waters, Marzano, & McNulty, 2003). The insights and perspectives of instructional coaches and principals can be analyzed to improve the systemic integration of this educational reform innovation. A qualitative methodology using a grounded theory approach was used to gather data and develop the theory. Eight instructional coaches and two principals were recruited from two medium-sized school districts in a Western State. These districts were purposefully selected because their instructional coaches engage in the core practices of high quality instructional coaching identified in the literature review (Borman & Feger, 2006). This study posits that principal attitudes and actions impact the capability of instructional coaches to increase teacher effectiveness. When principals demonstrate certain attitudes and actions, instructional coaches feel better able to increase teacher effectiveness. When these attitudes and actions are not present, instructional coaches feel their efforts in raising teacher quality are diminished. [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.]