This qualitative multiple case study concerned how school principals in charter, private, and public school settings experience autonomy, based on the schools' governance structures and accountability systems. Principal autonomy was defined as the authority that school principals exercise to lead staff effectively, to make decisions based on the needs of their constituents, and to make program improvements that meet or exceed federal, state, or local mandates. Participants' perceptions of principal autonomy were explored in relationship to four critical areas of educational leadership: (a) accountability; (b) personnel management; (c) resource allocation; and (d) instructional programs. The study also concerned the extent to which participants perceived the presence of an autonomy gap, which is the difference between the amount of autonomy principals think that they ought to possess to lead effectively and the amount of autonomy that that they actually possess, given their accountability constraints. Semi-structured interviews with principals, assistant principals, and teachers were conducted and relevant documents were collected. The three within-case analyses and one cross-case analysis resulted in five emergent themes: (a) principals possessed sufficient autonomy to achieve their educational goals but identified autonomy as a highly contextualized construct with multiple constraints; (b)autonomy gaps were found in the areas of personnel management and resource allocation; (c) principals in public, charter, and private schools were constrained by bureaucratic, performance, and/or market-driven accountability; (d) collaborative decision-making enhanced principal autonomy and, over time, revealed trust and faith among stakeholders in the principal's decision-making; and (e) autonomy was employed to promote instructional programs conducive to student learning and professional growth across all sites. Overall, this study contributed to the existing theoretical literature through the five emergent themes and the development of an autonomy continuum, both of which add to educational leadership theory. [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.]