Background: Community-based mentoring interventions can benefit high-risk youth. However, meta-analyses suggest that these benefits may be conditioned by proteges’ personality. Objectives: Associations between proteges’ personality traits and mentoring expectations, the quality of the mentoring relationship, the perceived mentoring contribution, and levels of adjustment at the end of mentoring were explored using the Big Five model. In addition, the possible moderation of proteges’ personality traits on the relationship between the quality of the mentoring relationship and proteges’ level of adjustment at the end of the intervention and the perceived benefits of mentoring was explored. Methods: Self-reports from proteges, parents, and teachers were used in a prospective research design. The sample consisted of 167 proteges (mean age = 9.58) from Perach, the largest community-based mentoring program in Israel. Results: Proteges’ agreeableness, extraversion, and openness were positively associated with their expectations. Agreeableness was positively associated with the quality of the relationship. Agreeableness, conscientiousness, and openness were positively associated with proteges’ social and academic adjustment at the end of mentoring, and with the perceived contribution of mentoring, whereas neuroticism and extraversion were negatively associated. Proteges’ personality traits moderated the correlations between the quality of the relationship and their conduct self-concept, as well as the parents’ perceived mentoring contribution. Conclusion: This study highlights the contribution of proteges’ personality in shaping their ability to benefit from mentoring in terms of adjustment and perceived contribution of mentoring.