A study of 118 secondary school principals in Oregon was conducted to examine the relationship of transformational leadership to secondary school principals' leadership performance. This study measured the transformational leadership of secondary school principals in Oregon using the "Multifactor Leadership Questionnaire (5X-Short)" (Avolio & Bass, 2004), which measures the following five categories of transformational leadership: (a) Idealized Attributes, (b) Individualized Behaviors, (c) Inspirational Motivation, (d) Intellectual Stimulation, and (e) Individualized Consideration. The secondary school principals' leadership performance was measured using the "Educational Leadership Improvement Tool" (DeFranco & Golden, 2003; Eugene School District 1J), which assessed principals' leadership performance in the following 10 areas: (a) Visionary Leadership, (b) Instructional Leadership, (c) Data-Driven Improvement, (d) Best Practices to Improve Student Learning, (e) Effective Management, (f) Organization to Improve Staff Efficacy, (g) Cultural Competence, (h) Community Leadership/ Inclusive Practice (i) Ethical Leadership, and (j) Socio-Political Context. A multivariate analysis of variance (MANOVA) showed that transformational leadership, as defined by Avolio and Bass (2004), had a significant relationship to the 10 leadership performance areas, as defined by DeFranco and Golden (2003) and Eugene School District 4J (2008). Overall results from the "Multifactor Leadership Questionnaire (5X-Short)" found that the majority of the principals rated their transformational leadership in each of the five areas examined at the "Fairly Often" level or higher. Out of the 10 leadership performance areas on the "Educational Leadership Improvement Tool," secondary school principals rated themselves highest in the area of Ethical Leadership and lowest in the areas of Cultural Competence and Visionary Leadership. A factorial analysis of variance (ANOVA) indicated that gender, age, and years of experience had no significant effect on transformational leadership and that no significant interaction occurred between gender, age, and years of experience. [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.]