States, districts, and schools are seeking ways to ensure teachers remain in the profession. It is more common than ever for a novice teacher to leave the profession within 5 years. Therefore, building a strong teacher self-efficacy is critical to developing and retaining novice teachers. This study examined how teacher self-efficacy fluctuated throughout the first year of teaching and the supports that were most beneficial to the first-year teacher. A mixed-methods design was applied to the study in order to attain a clearer understanding of how efficacy is developed in new teachers and how specific supports impacted the development. A Welch t-test was utilized to determine significant changes within teacher self-efficacy. The category of Instructional Strategies demonstrated significant change with a p-value of 0.022. Interview questions were designed to determine what factors contributed to the development of teacher efficacy. The sample included first year teachers from various states, represented elementary, middle, and high school teachers, as well as traditionally and alternatively certifications. The study found that teacher self-efficacy levels demonstrated the most significant changes in the area of instructional strategies and fluctuated within the first 9-12 weeks of beginning and at the close of the school year. [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.]