Children and youth coming from disadvantaged socioeconomic backgrounds are at risk of developing behavioural problems. This study examined the efficacy of a Yoga programme implemented in a low-socioeconomic status school, for the prevention of depression, anxiety, and aggression. After-school workshops were delivered twice a week during 12 weeks to 125 students in 5th, 8th, and 9th grades, enrolled in a school in Bogotá, Colombia. Participants were randomly assigned to an intervention and to a control group. Children's anxiety, depression, aggression, and some socioemotional competencies (specifically empathy, anger management, and prosociality) were quantitatively assessed before and after the intervention, by means of self- and peer-reported questionnaires. Qualitative data were also collected to assess children's perceived benefits from the workshops. Results suggested a potential of the programme to reduce children's anxiety problems, in particular. Results are discussed in terms of recommended improvements to the programme and its future evaluation.