Research has shown that young children's socio-emotional development may benefit from participating in a music programme. In this study, we explored the association between participation in a general music programme and the development of socio-emotional skills in relation to the duration of the programme. Children aged 4 and 5 (N=50), from a low socio-economic neighbourhood, participated in an 8- or 15-week music programme. Children's social skills development and emotion comprehension were measured. Teachers reported an increase in the social interaction and independence skills scores of the younger children and a decrease in the cooperation skills scores of the older children. Additionally, the older children showed an increase in their comprehension of emotions. The duration of the programme, however, did not yield any significant effect. Results suggest that the association between participation in a music programme and the development of social-emotional skills may be influenced by the age of the children.