Challenges new teachers face as they transition from their preparation program into their own classroom are well documented, however, the field struggles to retain those in the earliest phase of their career. Social support and teacher self-efficacy development both have been found to play a role in teacher retention. The purpose of this qualitative, multiple case study was to examine critical influences of social support on teacher self-efficacy as teachers transition from their preparation program into their own classroom, as well as the role teacher self-efficacy development plays in retaining early career teachers in the profession. Three cases were included in this study. Case one consisted of two student teachers, case two consisted of two first-year teachers, and case three included two early-career teachers with 2-5 years of teaching experience. Each participant was observed in their natural setting, talking with their cooperating teacher, mentor, professional learning community, or grade-level team. Participants also participated in a semi-structured interview and provided personal documents for analysis. Five themes emerged from two-cycle coding data analysis of initial and pattern coding as well as cross-case analysis: (1) Failed Supports, (2) A Desire for Feedback, (3) Seeking a Variety of Supports, (4) Working With and Supporting Others, and (5) Teacher Self-Efficacy Impacts Retention. Several subthemes were also revealed in two of the five themes developed from the data. Findings have implications for practice in both teacher preparation programs and those working with new teachers in K-12 school districts. [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.]