The focus of my research study is the effect of Principals' Leadership Styles on Teacher Job Satisfaction on teachers in the Rio Grande Valley. Teachers were asked to complete "The Multi-Factor Leadership Questionnaire" (MLQ) (Avolio & Bass, 1995), consisting of 45 questions, "The Abridged Job Descriptive Index" (aJDI) (Bowling Green University, 2009), consisting of 38 self-rated questions and a researcher-made demographic survey consisting of Principals' gender, teachers' gender, age, ethnicity, school level and experience to determine effects. This study focused on the followers' (teachers') perception of their Principals' Leadership Style based on the Full Range Model of Leadership, (Transformational, Transactional, and Passive Avoidant) and Teacher Job Satisfaction in the RGV. This study was non-experimental and utilized a convenience and voluntary sample consisting of (N = 192) educators. A paper and pencil method, was chosen, whereby, I walked onto campuses, with administrative permission, with my surveys and had teachers/colleagues confidentially complete the three surveys. My study's conclusion/results are as follows: (1) Transformational Leadership was positively and significantly associated with all six facets of Job Satisfaction (Supervision, Work, Pay, Promotion, People and Job in General). (2) Passive Avoidant resulted in negative, significant relationships with Job Satisfaction (Supervision, Work on present job). (3) Satisfaction (Supervision, Pay) at teachers' school level was positive at the Secondary level. (4) Teachers' age was negatively related to promotion. [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.]