Puberty is a period of rapid and radical physical, psychological and social change during which a child, in physiological terms, becomes an adult capable of reproduction. Adolescence refers as much to the psychosocial characteristics of development during puberty as to the physical changes. Adolescents with diabetes, who need to adhere to a complex medical regimen based around self-care throughout this period of development, face a series of particular and considerable challenges. In this article, Hala Tfayli and Silva Arslanian look at the hormonal, metabolic and behavioural changes that impact on diabetes care during the years of puberty, and outline strategies that could help young people to achieve good glycaemic control, and thus protect their health and well-being into adulthood.