The predicted upward trajectory in global myopia prevalence has sparked much interest and research investigating the causal mechanisms behind its development. Evidence of both genetic and environmental causes has been put forward, and this article aims to explore some of this evidence and how these two theories can be reconciled to explain the complex aetiology of myopia. As eye care professionals are ideally placed to offer lifestyle advice and optical interventions for reducing a child’s risk of myopia development and/ or progression, this article provides clinicians with a summary of what puts a child at risk of myopia, to help inform monitoring and intervention strategies.