Researchers in the field of educational administration have given little attention to the role of the associate principal. The research reported in this dissertation sought to fill that void through a close examination of the roles of the associate principals on two campuses in two different school districts. In addition to illustrating the role of the associate principal, the research examines how experience as an associate principal influences the careers of educational administrators. Data were collected primarily by means of semi-structured interviews with principals and district administrators as well as the associate principals themselves to provide multiple perspectives. Data were summarized in detailed interview logs, coded to discover the themes that were characteristic of each case, then analyzed to identify the patterns within and across the cases. The interviews were also analyzed as narratives reflecting on how experience as an associate principal can shape an educational administrator's career. The interview data were supplemented with documents relating to the associate principals, their campuses, and their districts. The results suggest that the associate principal position is a crucial step on the career ladder to a secondary principalship. Assistant principals with knowledge and skills in curriculum, instruction, and assessment are more likely to be selected as associates, and associates are more likely to be selected for principalships. The results also indicate that instructional leadership for associate principals in Texas focuses primarily on improving students' performance on the Texas Assessment of Knowledge and Skills and on increasing participation in and performance on other standardized tests, in particular Advanced Placement, SAT (formerly the Scholastic Aptitude Test), ACT (formerly American College Testing), and the PSAT/NMSQT (Preliminary SAT/National Merit Scholarship Qualifying Test).