There has been a wealth of research in recent years on the positive and negative aspects of youth sport participation. The Developmental Model of Sport Participation (CÃ´tÃ© & Fraser-Thomas, 2007) describes three separate pathways that youth can follow in their development: recreational participation, late specialization and early specialization. Many competitive sport programs are promoting early specialization in hopes that their athletes will gain an advantage over others; however, research indicates that youth who wait until adolescence to specialize in a given sport achieve greater performance (Moesch et al., 2011), experience less burnout and injury (Jayanthi et al., 2013) and less emotional stress (Gould, 2010). Therefore, the purpose of this study was to examine the relationships between youth hockey players' level of specialization, psychological need satisfaction (PNS) and dissatisfaction (PND), mental health and mental illness. Sixty one youth hockey players responded to online surveys composed of validated scales via FluidSurveys. Results indicated a significant difference between PNS according to specialization with early specializers reporting the lowest PNS and recreational athletes reporting the highest PNS (F = 6.28, p = .001). Further findings revealed a positive medium correlation between PNS and mental health (r = .39, p = .002) and a positive strong correlation between PND and mental illness (r = .65, p < .0005). There were also medium and negative correlations between PND and mental health (r = -.42, p = .001) and between PNS and mental illness (r = -.48, p < .0005). These results suggest that sport specialization may have an impact on psychological need (dis)satisfaction which is related to mental health and mental illness.