INTRODUCTION: Information regarding the prevalence of potentially traumatic events (PTEs), DSM-5 posttraumatic stress disorder (PTSD) and ICD-11 complex PTSD (CPTSD) in the Netherlands is currently lacking, as is data on treatment uptake and treatment barriers. We aimed to provide prevalence estimates for potentially traumatic events, PTSD and CPTSD in the Netherlands, describe treatment seeking behavior and explore associated risk factors. METHOD: We included a sample of 1690 participants aged 16 years and older across the Netherlands via the Longitudinal Internet studies for the Social Sciences panel, a true probability sample of households drawn from the population register by Statistics Netherlands. We recruited participants between September 1st, 2023, and November 1st 2023. All participants completed online self-report questionnaires, and a subset consented to an interview (n = 204). Instruments included the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5), the PTSD Checklist for DSM-5 (PCL-5) and the International Trauma Questionnaire (ITQ). RESULTS: The lifetime prevalence of any PTE was 81.5 %. The estimated lifetime prevalence of DSM-5 PTSD was 11.1 % and current prevalence 1.3 %. The estimated current prevalence of ICD-11 PTSD was 1.0 % and ICD-11 complex PTSD was 1.6 %. Especially females, younger adults, those with a lower education and those with a non-Dutch cultural background were at risk for PTSD. About half of the people with probable lifetime PTSD sought professional help and one-third received first-line PTSD treatment. Common reasons for refraining from seeking professional support included a lack of knowledge, shame and avoidance. CONCLUSIONS: PTEs, PTSD and CPTSD are common in the Netherlands and disproportionately distributed in society. Although evidence-based treatments for PTSD are available, only about one-third of those with lifetime PTSD receive first-line treatment. Findings underscore the need for targeted screening and preventative interventions, alongside public health campaigns aimed at enhancing knowledge and mitigating stigma about PTSD.