Despite years of attention, gender inequity persists in science, technology, engineering, and mathematics (STEM). Female STEM faculty, positive social interactions, and enrollment in advanced STEM secondary coursework are supportive factors in promoting female students' persistence in STEM fields. To address the gap in understanding these factors, this study employed a sequential mixed method design using a framework of social cognitive theory. Research questions focused on how levels of self-efficacy and perception of personal and social factors among female secondary students related to their enrollment in advanced STEM coursework and extracurricular activities in a rural New England school where gender parity exists. All 18-year-old female students (N = 82) were invited to complete the self-efficacy subsection of the Science Motivation Questionnaire II (SMQII). Self-efficacy and enrollment in advanced STEM courses and extracurricular activities were analyzed using a Pearson correlation (N =35). Self-efficacy levels did not correlate with the participants' enrollment in advanced STEM courses and extracurricular activities. In addition, a purposeful sample of participants (N =7) who completed the SMQII was used to conduct individual interviews investigating how the community of practice contributed to female students' decisions to pursue advanced STEM coursework. Two themes emerged: the roles of the personal landscape (e.g., resilient mindset) and the social landscape (e.g., peer interactions). Professional development materials to support staff in implementing a cognitive apprenticeship were created in response to the emergent themes. In addressing the lack of understanding of female secondary students' engagement in advanced STEM coursework, positive social change may be achieved by supporting a greater percentage of women who can pursue STEM career opportunities. [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.]