["Child and Adolescent Mental Health, EarlyView. ", "\n\nBackground\nNeurodevelopmental disorders (NDDs), including attention deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), intellectual disability (ID), and specific learning disorders (SLD), frequently co‐occur with psychiatric conditions (e.g. anxiety, depression). Although several reviews have attempted to summarise this evidence, reliable prevalence estimates remain limited. This umbrella review aimed to (a) determine the prevalence of co‐occurring psychiatric conditions among children and adolescents with NDDs and (b) compare prevalence rates with neurotypical peers.\n\n\nMethods\nAn umbrella review and meta‐analysis were conducted following PRISMA guidelines (PROSPERO CRD42023481585). Six databases were searched from inception to 18th February 2025. A total of 2342 systematic reviews were manually screened for inclusion. Systematic reviews were included if they reported the prevalence of mood, anxiety, fear‐related, OCD or behavioural disorders in children aged 3–18 with a DSM‐5‐defined NDD. Pooled prevalence estimates were calculated using random‐effects meta‐analyses. Comparative prevalence rates were analysed where control groups—neurotypically developing children—were utilized.\n\n\nResults\nOut of 2342 systematic reviews manually screened, 33 were included, which reported on 113 studies and 14,608 children with neurodevelopmental disorders (ADHD = 6234, ASD = 6257, ID = 1225, SLD = 892) included in the meta‐analyses. Pooled current prevalence ranged 2.8–14.1% for depressive disorders, 0.8–48.5% for anxiety disorders and 3.4–47.3% for behavioural disorders. Children with NDDs were significantly more likely to experience these conditions than neurotypical peers (odds ratios from 2.86 to 14.77).\n\n\nConclusion\nPsychiatric comorbidities are highly prevalent in NDDs. Screening for co‐occurring psychiatric conditions in NDDs is recommended.\n\n"]