The problem of teacher turnover in the United States has received significant attention from policymakers and district leaders. Improving teacher motivation is a concern and challenge for principals because they are faced with retaining highly qualified and capable teachers in the classroom. Researchers have indicated that principals can play a crucial role in motivating teachers. This nonexperimental correlational study used Deci and Ryan's self-determination theory and the leadership theories of Burns, Avolio, and Bass as a framework to address 2 research questions. The first research question examined the relationship between principal leadership style and teacher motivation, and the second question addressed principal leadership style and teacher retention. The sample included 55 certified teachers working in public middle school and high school in a southeastern state. The teachers completed electronic versions of the Multifactor Leadership Questionnaire, the Basic Needs Satisfaction at Work, and demographic questionnaire. For the first research question, results from a multiple linear regression showed transformational leadership to be a significant predictor of teacher motivation. For the second research question, a binary logistic regression did not support a relationship between principal leadership style and teacher commitment to teaching. The information gained from this study may benefit principals and teachers by informing leadership approaches for organizational change that may enhance teacher motivation. [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.]