Pulmonary vascular disease and pulmonary hypertension (PH) belong to the most relevant complications of congenital heart disease (CHD) in the long-term course. Although PH might lead to a severely impaired quality of life (QOL), there are no current studies comparing QOL in adults with CHD (ACHD) with and without PH. Therefore, this study aimed to systematically examine QOL in ACHD with and without PH in order to generate a more differentiated understanding of their overall health-status and to employ newly gained findings into general care of this particular patient population. In this comparative cross-sectional study, a representative sample of 803 adults with various forms of CHD with or without PH was analyzed. Data collection took place between September 2017 until February 2018 in a tertiary care center for ACHD. Medical data was retrieved from medical records. QOL was assessed using the EQ-5D-5L questionnaire. Descriptive methods, chi-square and t-tests were used to compare QOL of patients with and without PH. Of 803 patients, 752 patients had no PH [93.6%; 47.3% female; mean age: 34.9±11.83 (range, 18-86) years], 51 were identified with manifest PH [6.4%; 55.8% female; mean age: 41.9±12.17 (range, 21-69) years]. PH patients showed significantly worse overall QOL [mean no PH: 86.78±13.30 (8.2-100) vs. mean PH: 81.79±12.77 (43.6-100); 95% confidence interval (CI): 1.43 to 9.46; P=0.013], worse crosswalk index [mean no PH: 93.29±12.86 (-11, 100) vs. mean PH: 89.73±11.77 (47-100); 95% CI: 0.08 to 7.56; P=0.043], and worse VAS [mean no PH: 80.12±16.50 (15-100) vs. mean PH: 72.56±16.80 (40-100); 95% CI: 3.29 to 12.17; P=0.004]. However, after adjusting for age, only the VAS stayed significant (P=0.039). The QOL within the dimensions mobility (P<0.001), self-care (P=0.002), and usual activities (P=0.007), were significantly decreased in PH patients. Overall, anxiety and depression (11.08%) as well as pain and discomfort (11.03%) were the most impaired dimensions in both patient groups. Since QOL is a significant predictor of outcome, PH-CHD patients need an early provision of psychosocial, health promoting support in addition to dedicated care and targeted PH treatment. It is therefore pivotal to timely identify unique psychosocial impairments in order to enhance quantity and QOL in this particularly vulnerable patient population.