Women are underrepresented in science, technology, engineering, and math (STEM) in higher education institutions and the technology field and vulnerable to attrition. The reviewed literature suggests that the impact of other factors, beyond students' academic performance, leading to well-being and success and affecting female students' retention and persistence, needs attention. Moreover, opportunities for students to learn from one another, develop relationships, and build a sense of community should be investigated. The present study illuminates the experiences of a sense of belonging for female CS students who participated in CODE4her™ CS Mentorship Program for Girls (CODE4her). The embedded single-case approach bounded this phenomenological study. The participants were mentors in CODE4her between 2017 and 2022. The purposefully selected alumnae (n = 7) and current students (n = 5) recollected and described their lived experiences as mentors and CS students and how these experiences shaped their sense of belonging. Data were collected through semi-structured in-depth phenomenological and focus group interviews and an anonymous survey. Data analysis was performed in NVivo following the Modified van Kaam Method. The data analysis revealed that female CS students continue to perceive themselves as not belonging initially. Participating in CODE4her promoted feeling valued, respected, and part of a community. Mentors participated actively and assumed responsibility for their mentoring triads while practicing various skills. They felt supported by other women as they shared experiences, networked, and forged friendships. Students appreciated the program's mission and felt proud of being able to introduce CS to girls and make an impact on them. Mentors perceived that the program provided membership in a community that increased their confidence and a sense of belonging. The lack of a sense of belonging for female students in CS is a complex and significant problem without a panacea. A campaign to foster a sense of belonging must include a concerted effort that involves opportunities for extracurricular engagement for female students entering CS programs to quickly develop confidence and feel respected, valued, and supported. Furthermore, efforts to improve students' well-being are essential to such a campaign. Leadership implications are discussed. [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.]