The epidemiological transition towards non-communicable diseases is characterised by an upward shift in age of disease burden across the lifecourse. One response, within a suite of wider actions, would be to extend the upper age limit of paediatric practice to embrace adolescent health. We did an online survey to explore the upper age limit of paediatric care, obtaining responses from 1372 paediatricians in 115 countries. Marked variation in the upper age limit was apparent. Among high-income countries, a higher upper age limit was associated with greater disease burden in adolescents relative to young children (<5 years). Although paediatricians reported the mean upper age limit of paediatrics had risen over the past 20 years, the mean preferred age of 18·7 (SD 2·6) years was higher than the mean current age of 17·4 (SD 2·5) years (p<0·0001). Paediatricians reported the main reasons for the rising age over time was their greater awareness of adolescent health and leadership by professional associations. Reports of the quality of adolescent health education within national paediatric training suggest that this education is largely inadequate. A greater focus on adolescent health is required within paediatrics to ensure that the future paediatric workforce is appropriately equipped to respond to the changing disease burden across childhood and adolescence.