Abstract Objectives Type B aortic dissection (TBAD) is rare in patients aged ≤30 years, and data on this population remain limited. This study aimed to characterize the underlying aetiology, and outcomes of invasively treated young patients with TBAD, with a focus on the impact of heritable thoracic aortic disease (HTAD). Methods A retrospective multicentre analysis was conducted across 19 international aortic centres, including 139 patients aged ≤30 years with TBAD. Patients with chronic TBAD (n = 42) were excluded for the final analysis. The cohort was classified as uncomplicated (n = 86) or complicated (n = 53) TBAD. Clinical, radiologic, intraoperative, and postoperative data were collected using standardized forms. Outcomes were compared between subgroups defined by TBAD complexity, HTAD status, and surgical strategy. Kaplan-Meier and Andersen-Gill analyses were used for survival and recurrent aortic intervention, respectively. Results Mean follow-up time was 6.5 years. HTAD was identified in 57% of patients. Most presented with uncomplicated TBAD (62%), while high-risk uncomplicated cases were uncommon. Endovascular repair was predominant in complicated TBAD, while open repair was more frequent in uncomplicated cases. Early mortality was low (n = 3), and mid-term survival was excellent across all subgroups. HTAD was a significant predictor of recurrent aortic interventions (HR = 3.3, P = .004). No significant differences were observed in survival or reintervention rates between uncomplicated and complicated TBAD or between operative strategies. Conclusions In young patients, TBAD predominantly occurs in the context of HTAD. Both open and endovascular repair are associated with excellent early outcomes and mid-term survival. However, HTAD remains a significant predictor of recurrent aortic interventions.