Providing effective administrative leadership that has a positive impact on student achievement often is problematic for school principals. Research suggests that collaboration and shared decision making are functions of effective leadership, and according to the premises of effective school instructional leadership, leadership should change with respect to a given situation. The purpose of this study was to investigate the relationship between principals' perceptions of the temperament component of their leadership style and student achievement in adequate and high performing schools. All students in this district are required as part of the No Child Left Behind Act to score proficient in reading and math by the year 2014. The theoretical foundation of this study is effective school instructional leadership theory, which suggests that leadership should change with respect to a given situation, and that factors such as temperament influence the ability to assume a context specific leadership approach. Temperament dimensions of principals were measured by the Majors Personality Type Indicator (Majors PTI). Student achievement was measured by the Academic Performance Index (API) score according to the state curriculum tests in a large suburban school district. A group of 17 schools were classified as either adequate achieving schools or high achieving schools based on API scores. Spearman correlation analyses indicated a statistically significant association linking only the Majors PTI classification of ESTJ with the high achieving school classification (rho = 0.528, p = 0.029). The findings linking principals' individual temperament and student achievement have the potential to influence social change by better informing internal career coaching and succession planning within schools as well as selection processes for leadership positions. [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.]