ABSTRACT We aim to validate a European-Portuguese version of the Hypertension Knowledge Test (HKT) questionnaire and examine its factorial structure with a confirmatory factor analysis (CFA). A process of translation and back-translation was performed. A cross-sectional study was developed in which all adult patients taking at least one antihypertensive drug were invited to participate. Data on personal and family history were collected, and the HKT, Strelec, and the Batalla questionnaires were administered. We enrolled 304 patients with a mean age of 68.12±10.83 years. The mean score of HKT was 15.33±2.79. CFA indicated that the construct being tested was unidimensional, and Cronbach’s alpha (α=0.65) showed that the instrument had an acceptable internal consistency. When evaluating concurrent validity, HKT was significantly correlated with the Batalla and Strelec scores. Thus, the Portuguese version of HKT (HKT-pt-PT) can be used either in research or in clinical practice. With this version, a potential standard exists to evaluate knowledge about hypertension, which could avoid the practice of using non-validated questionnaires in Portugal and allow the cross-sectional and longitudinal comparability of studies.