Introduction There is a dearth of psychological interventions for patients with cleft lip and/or palate (CL/P). Objective To evaluate the influence of music lessons on the socio-emotional wellbeing of children with CL/P. Setting This study was conducted at Asociación San Lucas (Moyobamba, Peru), which has a multidisciplinary programme for children with CL/P. Recorder lessons are offered to all patients aged 6-8 years. From age eight, the children can switch to flute, clarinet, violin, viola or cello. Materials and methods The Glasgow Benefit Inventory (GBI), a post-intervention questionnaire, was administered to all 26 children participating in the music programme. Results Mean GBI scores per question ranged from 59.62 (SD: 31.68) to 92.31 (SD: 23.21), showing an overall positive effect of the music lessons on the patients' socio-emotional wellbeing. Playing a musical instrument gave the children satisfaction and self-confidence. The children lost much of their shame, became less shy, and participated more in social activities. In a non-significant numerical trend, boys, flute/clarinet players and orchestra players had higher mean GBI scores than, respectively, girls, string players and children who did not play in the orchestra. Conclusions Quantitative and qualitative analysis indicated a positive influence of music lessons on the patients' socio-emotional wellbeing. © 2023, The Author(s), under exclusive licence to the British Dental Association.