Angelman syndrome (AS) is a congenital syndrome with a prevalence of 1:15,000. Individuals with AS often have severe intellectual disability, typical dysmorphic signs, and behavioral problems. The aim of the study was to investigate the rate of incontinence and associated psychological problems in children and adults with AS. Ninety children (4–18 years) and 54 adults (18–31 years) with AS were recruited through a parent support group (55.6% male, mean age 15.1 years). The Parental Questionnaire: Enuresis/Urinary Incontinence, the Incontinence Questionnaire-Pediatric Lower Urinary Tract Symptoms (ICIQ-CLUTS), as well as the Developmental Behaviour Checklist for parents (DBC-P) or for adults (DBC-A) were filled out by parents or caregivers. 85.6% of individuals with AS were affected by at least one subtype of incontinence (82.7% nocturnal enuresis (NE), 64.7% daytime urinary incontinence (DUI), and 57.1% fecal incontinence (FI)). 52.5% of the children and 32.6% of adults reached a clinically relevant DBC score. Incontinence was not associated with behavioral problems. NE and DUI were associated with genotype and epilepsy. Conclusion: Children with AS have high rates of incontinence. Many adults are still affected by NE, DUI, or even FI. Screening, assessment, and treatment of incontinence in individuals with AS are recommended.What is Known:• Incontinence in persons with Angelman syndrome (AS) is associated with younger age, lower level of adaptive functioning, and epilepsy.What is New:• Children and teens with AS are at special risk for incontinence, but older persons are also affected.• Comorbid epilepsy is significantly associated not only with nocturnal enuresis (NE) but also with daytime urinary incontinence (DUI). Underlying genotype is significantly associated with incontinence.