Recent labour market research has shown that a good education comprises investment in both cognitive and non-cognitive skills. We examine the impact of a long-term programme designed to raise non-cognitive skills of children and adolescents in slums in Bombay. We use a cross-cutting design with two comparison groups of peers for young adults who have attended the programme until leaving high school to analyse whether, compared to those from a similar environment and background, enrollment in the programme demonstrably raises such skills. We find evidence of substantial impacts on both self-esteem and self-efficacy (of about one standard deviation), as well as evidence of a smaller impact on life evaluation and aspirations. Furthermore, in line with the literature, both self-esteem and self-efficacy are positively related to success in school-leaving examinations and initial labour market outcomes.