Research has demonstrated the importance of various forms of mentoring across multiple contexts. However, the topic of informal peer mentors has not been sufficiently explored. This study investigated the role of peer mentors in encouraging participation in voluntary development activities (i.e., capitalization). An online survey was completed by 288 undergraduate students. As hypothesized, mentoring was positively related to high levels of participation in capitalization activities and intentions to mentor in the future, and capitalization participation was positively related to higher levels of student satisfaction, continuance commitment, and career involvement. Contrary to expectations, capitalization participation was not significantly related to affective commitment. However, the mentoring items did not appear to load as separate factors for psychosocial and career-related functions, preventing the testing of relationships with these specific dimensions of mentoring. Research implications, limitations, and future directions for research are discussed.