Despite the presence and potential impact of instructional coaches, many schools are not experiencing significant improvements in teachers' practices or student achievement. In gaining more insight into forces that impact instructional coach effectiveness, this study (a) explored the relationship between sources of instructional coaching efficacy and dimensions of instructional coaching efficacy ["Mathematics Content & Mathematics-Specific Pedagogy" ("ME"), "Student Centered & General Pedagogy" ("SE"), "Interpersonal & Communication Coaching" ("IE"), and "Personal Coach Characteristics"]; and (b) explored the relationship between dimensions of instructional coaching efficacy and instructional coach outcomes. Participants included teachers (n=144) and their instructional coaches (n=19), from elementary schools located within a large urban school district in the southeastern U.S. Teachers completed an adapted Coach Effectiveness Questionnaire (Yopp, Burroughs, & Sutton, 2010), which assessed their perceptions of coach outcomes. Coaches completed an adapted Coach Efficacy Questionnaire (Yopp, Burroughs, & Sutton, 2010), which assessed their perceptions of source information and dimensions of instructional coaching efficacy. Significant correlations were found between the source Degree Major (Math) and ME (r = 0.534). Moreover, canonical correlation analysis showed that dimensions of instructional coaching efficacy were significantly associated with instructional coach outcomes, F(45, 363.21) = 2.326, p less than 0.001. Particularly, regression analyses found IE to be predictive of instructional coach behavior (beta = 0.395, t = 3.534, p less than 0.01); instructional coach impact (beta = 0.343, t = 2.982, p less than 0.01); and teacher satisfaction (beta = 0.264, t = 2.272, p = 0.025) with their instructional coach. Mathematics content & mathematics-specific coaching efficacy (ME) was also predictive of teacher satisfaction with their instructional coach (beta = 0.181, t = 2.012, p = 0.046). These results were generally supportive of the theoretically expected relationships between instructional coaching efficacy and instructional coach outcomes. Lastly, context and individual instructional coach qualities accounted for a substantial amount of variance in instructional coach outcomes. These findings are consistent with previous research that link situational factors and individual differences to coach effectiveness (Horn, 2002). [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.]