Resilience, as defined by the literature, deals with the relationship between individuals and their environment. This capstone project followed elementary students over a three-year period to investigate and determine the impact a co-teaching intervention model has on resilience, grade-point average (GPA), state testing scores in English language arts (ELA) and mathematics, and school connectedness in one control group fourth-grade class and one fifth-grade experimental class at a moderately sized elementary school in Southern California. A mixed method approach was used. Qualitative data was collected from pretest participants in their fifth-grade year to gain insight into their perspectives about the participation in a math co-teaching model as fourth graders. Findings from t-test analysis showed mixed results in the impact of the intervention on resilience skills and state testing for both ELA and math. Overall GPA improvement was consistent with intervention. Gender differences were noted, wherein females showed better performance in math, health and well-being, valuing education, academic confidence, and connectedness to teachers. Males, however, performed better in connectedness to adults, intrinsic motivation, stress, GPA, and ELA scores. Students' overall responses indicated an increased connectedness with school and positive feedback regarding the student-teacher ratio, greater accessibility of teachers, and multiple teaching styles to meet student needs. Based upon this project, encouraging a lower student-teacher ratio is recommended. [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.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]