Many of the considerable number of young people who identify as transgender or gender diverse do not conform to traditional binary notions of gender (male vs female), and instead have a non-binary gender identity. This narrative Review summarises literature related to the sociodemographic and clinical profiles of young people with a non-binary gender identity. Young people identifying as non-binary form a substantial minority of the general population. They experience lower levels of support and are at increased risk of experiencing abuse and victimisation than young people who are cisgender. Furthermore, compared with young people who are transgender and binary, people who identify as non-binary experience less access to trans-specific health care. Young people identifying as non-binary have poor mental health outcomes, with high rates of depression, anxiety, and suicidal ideation that were found to be similar if not higher than in those who are transgender and binary. This Review highlights that young people who identify as non-binary are highly vulnerable and likely to have important health-care needs.