Autism spectrum disorders (ASD) are a set of neurodevelopmental disorders characterised by behavioural, communication and social impairments. The prevalence of sleep disturbances in children with ASD is 40-80%, with significant effects on quality of life for the children and carers. This systematic review aimed to synthesise evidence of the effects of behavioural interventions to improve sleep among children with ASD.Databases (MEDLINE, PsycINFO, CINAHL, ScienceDirect, Autism Data, CENTRAL, ClinicalTrials.gov and Current Controlled Trials) were searched for published, unpublished and ongoing randomised controlled trials evaluating the effect of non-pharmacological interventions for insomnia in children with autism spectrum conditions.Three studies met the inclusion criteria, one provided actigraphy data, one Children's Sleep Habits Questionnaire (CSHQ) data, and one both actigraphy and CSHQ data for use in meta-analyses. There were significant differences between the behavioural intervention and comparison groups (actigraphy data) for total sleep time (24.41 minutes, 95% CI 5.71, 43.11, P = 0.01), sleep latency (-18.31 minutes, 95% CI -30.84, -5.77, P = 0.004) and sleep efficiency (5.59%, 95% CI 0.87, 10.31, P = 0.02). There was also a favourable intervention effect evident for the subjective CSHQ data (-4.71, 95% CI -6.70, -2.73, P<0.00001). Risk of bias was low across several key domains (randomisation, allocation concealment and reporting), with some studies being unclear due to poor reporting.There are very few high quality randomised controlled trials in this area. Here we provide initial synthesised quantitative evidence of the effectiveness of behavioural interventions for treating sleep problems in children with ASD.Protocol was registered (CRD42017081784) on the International Prospective Register of Systematic Reviews (http://www.crd.york.ac.uk/PROSPERO).