Global prevalence of childhood overweight and obesity have increased drastically in the past years, including in Malaysia. School-based obesity intervention is important to promote healthy eating and behavioural change. Many obesity interventions have been conducted to combat childhood obesity; however, the sustainability of childhood obesity interventions are often overlooked. This study aimed to explore the factors that influenced sustainability of Juara Sihat intervention programme in Kuala Lumpur primary school. Face-to-face in-depth interviews were conducted with 26 children aged 12- 14 years old whom participated in the Juara Sihat intervention programme were purposively selected. Data was transcribed verbatim and analysed using thematic analysis. The main themes identified as motivators are (1) support from family, facilitators, school teachers, and friends; (2) physical activity and healthy eating practices after intervention; (3) self-awareness; (4) knowledge on food pyramid and healthy eating; and (5) home environment. While the barriers are (1) knowledge inconsistency; (2) own safety; (3) peers influence; (4) self-attitude; (5) boredom towards programme. The results showed that the main promoting factor for sustainability of Juara Sihat intervention programme is continued practice of physical activity and healthy eating, while the main barrier is knowledge inconsistency. Therefore, school-based obesity intervention programmes should consider these promoting and hindering factors that could influence the sustainability of intervention programmes. Future studies should consider those factors during program intervention planning especially when factors that influence implementation and sustainability are carefully considered and taken care of to ensure long-term success.