The purpose of this research was to study the three leadership styles on the Full Range Leadership Model (FRLM) practiced by high school administrators in the educational organization. The aspects of studying leadership styles was to determine the degree high school administrators practiced leadership styles; the degree of perceptional congruence of leadership styles, factors, and outcomes by administrators and teachers; and the degree of relationship between leadership styles and leadership outcomes. This research study was built on prior research studies by Avolio and Bass (1998; 2002; 2004) and their Full Range Leadership Model. Working on prior studies of the Full Range Leadership Model, this study employed a cross-sectional survey design. To accomplish results, the "Multifactor Leadership Questionnaire" ("5x-Short"), developed by Avolio and Bass (2004) to assess their Full Range Leadership Model, was used by the researcher. Leader and rater forms of the MLQ (5x-Short) were used to survey 36 high school administrators and 784 teachers in two public school systems in Middle Tennessee. The data was analyzed to resolve four research questions. The researcher employed descriptive statistics, independent samples t-Test, and Pearson r correlations. The findings in this study showed consistency with the Full Range Leadership Model and the theoretical framework for effectiveness regarding the following: (1) transformational leadership was the highest ranked style practiced by high school administrators; (2) active transactional leadership: contingent reward and management-by-exception (active) were found to be practiced second; and, (3) transactional leadership management-by-exception (passive) and laissez-faire leadership were found to be practiced least. The findings of the study were consistent with Avolio and Bass's (2002) findings that leaders practice all three leadership styles to varying degrees depending on what each administrative situation compels. [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.]