In this mixed-method study, participation in a peer mentoring program's impact on ethnic identity development is explored, with particular emphasis on Asian American mentors. There has been a lack of research on the effects on the mentors who participated in peer mentoring programs. This study intended to provide an understanding of how the mentoring program contributes to their ethnic identity development. The quantitative phase consisted of a pre- and post-survey based on the Multigroup Ethnic Identity Measure (Phinney, 1992) to identify the respondents' current stage of ethnic identity (N = 63). The survey was conducted between August 2021 and April 2022. Pre- and post-survey results revealed no statistically significant difference for the means of the students' overall ethnic identity achievement; identity search subscale; or affirmation, belonging, and commitment subscales. The qualitative phase was exploratory, consisting of a phenomenological analysis of open survey responses and 13 in-depth interviews, which were conducted between January 2022 and March 2022. Purposeful selection was applied to select Asian American undergraduate students serving as peer mentors. The use of Colaizzi's (1978) method of phenomenological analysis allowed for the moving of significant statements to four clustered themes that describe a peer mentor's ethnic identity development through their participation in an ethnic-based mentoring program. Findings suggested participation in an ethnic-based peer mentoring program provides opportunities to explore and understand their ethnic identity. Recommendations are made which institutions can use to enhance peer mentors' ethnic identity development. [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.]