Youth mentoring is defined as a close, interpersonal relationship between a young person and a more experienced adult. The quality of the youth-mentor relationship is critical to youth mentoring interventions and thus it is imperative that relational dynamics, such as match satisfaction, are explored and understood in order to further inform programme development.Methods: This research outlines a secondary analysis of quantitative data gathered as part of a large scale, longitudinal evaluation of the Big Brother Big Sister (BBBS) of Ireland programme (Dolan et al., 2011). Specifically, 76 young people and their mentors who took part in the Irish BBBS programme completed questionnaires assessing their perceptions of the quality of their mentoring relationship. Multiple waves of data collection were completed over a two year period. Young people also reported on their developmental outcomes at each time point.Results: Results from a series of hierarchical regression analyses suggest that both mentor and mentee's perceptions of match satisfaction are significantly associated with youth developmental outcomes over time.Discussion: Overall, this research reports several findings that have relevance for youth mentoring research and practice and expands our understanding of how match satisfaction can impact the success of formal youth mentoring programmes, such as the BBBS programme.