BackgroundChildren and young people with neurodisability often need help to achieve socially acceptable bladder and bowel control. Approaches vary depending on whether or not the impairment results from spinal cord pathology that impairs motor control and sensation of the bladder and bowel. Currently, there is uncertainty about which interventions are effective.ObjectiveThe objective was to summarise the available evidence on and current practice for improving continence in children and young people with neurodisability.DesignA systematic review of the effectiveness, cost-effectiveness and factors that modify intervention implementation, alongside a cross-sectional, online survey of current practice with health professionals, parent carers, school and care staff and young people with neurodisability.ResultsTwelve databases were searched in the review, resulting in 5756 references; 71 studies (72 papers) were included in the analyses. Most of the evidence was for children with spinal cord pathology, which involved evaluations of pharmacological approaches and surgical techniques, whereas the evidence pertaining to those with non-spinal-cord-related pathology tended to be for behavioural interventions. The methodological quality of studies was rated as being moderate to poor. There were three robust qualitative studies about the experience of continence among children with spinal cord pathology. We found substantial heterogeneity across the interventions that we evaluated in terms of quality, study design and outcomes measured. No economic studies were found. The results were synthesised narratively and reported in text and tables. We did not find any eligible studies evaluating interventions using toilet and clothing adaptations in the review, although the survey highlighted that these types of interventions are frequently used and considered. In total, 949 people responded to the survey: 202 health professionals, 605 parent carers, 122 school and social care staff, and 20 young people. The survey results illustrated the different roles that professionals have in improving continence, highlighting the importance of a multidisciplinary approach to supporting children and young people and their families. Clinicians employ a range of assessments and interventions to improve continence or independent toileting, depending on the needs of the child.LimitationsQuantitative studies in the review were not methodologically robust. The survey had a risk of response bias.ConclusionsOur research found a dearth of good-quality evidence for many of the interventions currently in use, and no evidence of experiences of implementing interventions for children with non-spinal-cord-related pathology. There was also no evidence of cost-effectiveness of any of the interventions.Future workThere is a need to involve young people and families in the design of high-quality evaluative research for interventions that aim to improve continence. This is especially the case for children with autism and learning disability, who have been neglected in previous evaluative and qualitative research. We recommend better training for health, education and care professionals about toileting, informed by evidence and the lived experiences of children and their families. We recommend a joined-up multidisciplinary and holistic approach to improving continence to maximise independence, dignity and comfort. It is vital that children and young people with neurodisability have early access to regular, integrated assessment of their bladder and bowel health, and are fully supported with appropriate personalised treatment.Study registrationThis study is registered as PROSPERO CRD42018100572.FundingThis project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full inHealth Technology Assessment; Vol. 25, No. 73. See the NIHR Journals Library website for further project information.