The Société Internationale d’Oncologie Pédiatrique [International Society of Paediatric Oncology] (SIOP), founded in 1969, aims to improve the lives of children and adolescents with cancer through global collaboration, education, training, research and advocacy. The annual congress provides the opportunity to share late-breaking research, clinical experiences and debate, with experts worldwide. SIOP’s six Continental Branches represent their constituent members in North America, Oceania, Latin America, Africa, Europe and Asia and bring best practices and recent research findings of value to their specific patient populations. In 1990, the SIOP Board of Directors addressed the formerly predominantly European/North American society transforming into a global association by establishing a scholarship program to bring low- and middle-income country (LMIC) paediatric oncologists and nurses to SIOP meetings. A major achievement was SIOP’s acceptance as a World Health Organisation (WHO) non-state actor in official relations in 2018, joining 220 non-governmental organisations, international business associations and philanthropic foundations with this privilege. SIOP supports advocacy with WHO member states and civil society to highlight the specific needs of cancer in this age-group through key programs especially supporting the WHO Global Initiative for Childhood Cancer. Sustained improvement in childhood cancer outcomes has paralleled the integration of research with care; thus, SIOP launched a Programme for Advancing Research Capacity for funding selected clinical trial groups in LMICs. SIOP supports south-south partnerships, and the principles elegantly expressed in SIOP Africa’s checklist for co-branding projects, that include the prioritisation of local needs, cultivation of local expertise and commitment to equitable partnerships. SIOP now counts approximately 3,000 members from over 128 countries; 39% are from more than 60 LMICs. SIOP members have multidisciplinary expertise on all aspects of childhood cancer care working in collaboration with key stakeholders including governments, civil society organisations and funders to improve the lives of children/adolescents with cancer everywhere in all ways.