Background: Turner syndrome is the result of a missing X chromosome, partially or completely, in phenotypic girls. This can cause an array of medical and developmental difficulties. The intelligence quote has previously been described as uneven but considered within normal range. Although a social, intellectual and psychiatric profile is described in females with Turner syndrome, it is unclear to what extent they meet the clinical criteria for neurodevelopmental or psychiatric diagnoses. The aim of this study was to examine the prevalence of neurodevelopmental and psychiatric disorders in females with Turner syndrome. Methods: A retrospective case-control study was performed with a total of 1392 females with Turner syndrome identified through the Swedish National Patient Register and compared with 1:100 age- and sex matched controls from the general population. The association between Turner syndrome and diagnoses of neurodevelopmental and/ or psychiatric disorders were calculated using conditional logistic regression and is presented as estimated risk (Odds ratio, OR, 95% Confidence interval, CI) in females with Turner syndrome compared with matched controls. Results: Females with Turner syndrome had higher risk of any neurodevelopmental or psychiatric disorder (OR 1.37, 95% Cl 1.20-1.57), an eightfold (OR 8.59, 95% CI 6.58-11.20) increased risk of intellectual disability and a fourfold (OR 4.26, 95% CI 2.94-6.18) increased risk of autism spectrum disorder compared with the controls. In addition, females with Turner syndrome had an increased risk of a diagnosis of psychotic disorders (OR 1.98, 95% Cl 1.36-2.88), eating disorders (OR 2.03, 95% Cl 1.42-2.91) and behavioral disorders (OR 2.01, 95% CI 1.35-2.99). Conclusions: Females with TS have an increased risk of being diagnosed with any neurodevelopmental and psychiatric disorder. This warrants extensive assessment of intellectual and cognitive functions from early ages and increased psychiatric vigilance should be a part of lifelong healthcare for females with TS.