The purpose of this mixed-methods study was to increase grit, growth mindset, and self-efficacy in pre-adolescent students attending a K-5 public elementary school in Northwest New Mexico by implementing intervention activities in which students were given opportunities to learn and develop grit and growth mindset, thus resulting in improved self-efficacy and academic performance on a formative English Language Arts (ELA) and Math progress monitoring assessment. I used teachings from the Navajo epistemology, "Sa'ah Naaghai Bik'eh Hozhoon," as the foundation for teaching students about the constructs of grit and growth mindset through interventions meant to strengthen their resolve. Interventions included conversing with people with whom they could identify who had overcome challenging situations, learning how the brain learns new things, using positive self-talk, reading about characters overcoming challenges, and engaging in classroom discussions and activities. Thirteen children participated in the 6-week intervention. Eighty-five percent of the students were Native American. Students did not grow significantly on the 8-Item Grit Scale for Children, t[subscript 24] = -0.979, p = 0.234. However, students did grow significantly on the Implicit Theories of Intelligence Children's Self-Form, t[subscript 24] = 3.980, p = 0.002, and on the Self-Efficacy Scale for Children, t[subscript 24] = -2.83, p = 0.015. The participants' responses to focus group questions showed an increased use of words related to grit, growth mindset, and self-efficacy. Recommendations are included to assist classroom teachers, particularly those working with Native American children, in helping their students develop grit, growth mindset, and self-efficacy. [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.]