Background: Approximately half of the children with attention-deficithyperactivity disorder continue to meet diagnostic criteria in adulthood.The prevalence of adult attention-deficit hyperactivity disorder is reported between 2.5% and 4.4% and is associated with significant impairmentin quality of life and increased psychiatric comorbidity. Attention-deficithyperactivity disorder in adults remains mostly undiagnosed and/or untreated despite the availability of effective treatments. The majority ofpeople who do not receive necessary treatment are in the nonclinical ornonpsychiatric clinical population. Screening is an important step for diagnosing adults with attention-deficit hyperactivity disorder. Yet, thereare no valid and reliable screening questionnaires calibrated for the Diagnostic and Statistical Manual for Mental Disorders-5 in Turkish.Aims: We aimed to test the reliability and the validity of the Adult Attention-Deficit Hyperactivity Disorder Self-Report Scale-5 screeningquestionnaire designed according to DSM-5 in the Turkish population.Study Design: Methodological and cross-sectional study.Methods: The translation was carried out according to the WorldHealth Organization Composite International Diagnostic Interviewtranslation guide using a linguistic adaptation approach. We used aconvenience sampling method to recruit an individual with adult attention-deficit hyperactivity disorder (n = 68) and a control group (n = 68).The participants completed a sociodemographic form, 6-items AdultAttention-Deficit Hyperactivity Disorder Self-Report Scale-5, and theprevious version 18-items Adult Attention-Deficit Hyperactivity Disorder Self-Report Scale-v1.1 for the concurrent validity analysis. For thediagnostic validity, clinical diagnosis made by psychiatrists accordingto the Diagnostic and Statistical Manual for Mental Disorders-5 criteriawas used. Internal consistency and item-total correlation coefficients,exploratory factor analyses, correlation with Adult Attention-DeficitHyperactivity Disorder Self-Report Scale-v1.1, and receiver operatingcharacteristic curve analysis were conducted.Results: The internal consistency measured by Cronbach alpha was0.869. Item-total correlation coefficients were calculated to be between 0.602 and 0.717, and the correlations were statistically significant (P < 0.0001). The Adult Attention-Deficit Hyperactivity DisorderSelf-Report Scale-5 showed to have a unidimensional factor structureexplaining 60.54% of the variance. The correlation between Adult Attention-Deficit Hyperactivity Disorder Self-Report Scale-5 and AdultAttention-Deficit Hyperactivity Disorder Self-Report Scale-v1.1 totalscore was calculated as 0.992 (P < 0.0001), and that between AdultAttention-Deficit Hyperactivity Disorder Self-Report Scale-5 and AdultAttention-Deficit Hyperactivity Disorder Self-Report Scale-v1.1 attention-deficit subdimension was 0.868 (P < 0.0001). In the receiver operating characteristic analysis of Adult Attention-Deficit HyperactivityDisorder Self-Report Scale-5, the area under the curve was found to be0.916. The cut-off score was calculated as 9 of 10 with a sensitivity of85.2% and specificity of 89.7%.Conclusion: Adult Attention-Deficit Hyperactivity Disorder Self-Report Scale-5 is a valid and reliable self-report measure to assess andscreen attention-deficit hyperactivity disorder in the Turkish population. It may be useful for both clinical and population studies.