Toilet training is one of the key developmental milestones of early childhood and there is growing evidence that it is now being initiated later than it was 50 years ago. This article explores the reasons why this is happening and considers the effect on children with autism and related conditions. It also examines the literature to discover the approaches to toilet training for this group. Research into this area has generally focused on small numbers of children and incorporated modified versions of Azrin and Foxx’s (1971) rapid toilet training method. Suggestions are offered about the most appropriate advice to give parents and carers of children with autism and related disorders, and the importance of addressing toilet training at an early stage.