The single most important factor for the success of a student in school is the teacher, yet many factors impact the teacher's ability to do the job as effectively as possible. Data exists regarding the multiple influences that affect the teacher's sense of self-efficacy, however, specific data regarding leadership behaviors is limited. Research shows that student achievement is affected by the teacher, therefore it is imperative to determine what leadership behaviors impact teacher efficacy the most. The purpose of this quantitative study was to explore the impact of principal behaviors on teacher efficacy. Also, the study sought to compare the derived results from elementary school data with that of middle school data to determine if a difference exists between principal behaviors and teacher efficacy at both levels. A multivariate multiple regression was used to analyze the findings. This method was used due to the multiple independent, as well as multiple dependent variables that exist within both measures; the Teacher Sense of Self Efficacy Scale Long Form and the Leadership Practices Inventory. The study found that there was no significant impact of principal behaviors on teacher efficacy for the participating school district. There was, however, a significant difference in the self-efficacy of elementary school and middle school teachers with regard to student engagement. While elementary teachers rated themselves relatively high in student engagement, middle school teachers rated themselves lower in their ability to engage students in learning. District leaders should consider professional development in building middle school efficacy in student engagement. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]