The current study investigated toileting problems in one hundred and twenty-seven children and adolescents with parent-reported diagnoses of autism spectrum disorder. Toileting refers to the accomplishment of various unprompted behaviors, including recognising the need to go to the toilet, and waiting before eliminating. The relationship between toileting problems and age, gender, intellectual disability, gastrointestinal symptoms, sleep problems, comorbid psychopathology, quality of life, and adaptive functioning were examined using parent-report questionnaires. The most common toileting problems were, "Does not independently perform most self-help tasks", "Has toilet accidents during the day", and "Parent/caregiver notices smears in underwear". Gender, presence of intellectual disability, gastrointestinal symptoms, and comorbid psychopathology were significant predictors of toileting problems in this study. The gastrointestinal symptoms of constipation and bloating were found to be significant predictors of toileting difficulties. Specifically, constipation predicted accidents and physical problems associated with toileting, and bloating predicted social/emotional factors and physical problems. A small negative correlation was observed between total toileting problems and total health related quality of life. An increase in physical toileting difficulties was associated with lower quality of life.