The purpose and goal of this quantitative method, causal-comparative study was to explore the impact of a year-long mentorship program on the self-efficacy, collective efficacy, perceived support, retention plans, and effectiveness of novice (i.e., 1st-3rd year) teachers in a rural, public school district in Mississippi. The mentorship program sought to prepare and equip novice teachers to become highly effective educators. The study focused on a targeted group of 141 certified teachers that included a subgroup that participated in a teacher mentorship program. Pre- and post-surveys measured self-efficacy beliefs, collective efficacy, perceived support received from administration and colleagues, and retention plans. The Mississippi Department of Education professional growth system rubric was used to measure teacher effectiveness before and after the mentorship program. Results confirmed that self-efficacy, perceived support, and teacher effectiveness significantly increased following the mentorship program. Ultimately, this study highlights the importance of providing ongoing, intentional support to novice teachers as they navigate the challenges of their first years in the profession. [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.]