Background: Behçet’s disease (BD) activity assessment is a major concern since a treat-to-target approach may lead to a better prognosis. The first patient-reported assessment instrument, the Behçet's Syndrome Activity Score (BSAS), is useful for routine clinical use. Aim: To evaluate the validity and reliability of the translated Arabic version of BSAS (Ar-BSAS) in the assessment of BD activity and discriminate its cut-off point or disease activity. Method: Seventy BD patients were included in the study. The BSAS was translated into Arabic language. The reliability and validity were evaluated. Results: The Ar-BSAS of each item and the total score demonstrated a high internal consistency and Cronbach’s alpha coefficient of 0.881, to 0.997. A significant positive correlation was found between the total score of the BSAS with the BDCAF (r =0.891, p <0.001**) and the BSAS with the MHAQ (r =0.813, p <0.001**), and between the total score of BSAS and ESR and CRP indicating high convergent validity. The BSAS cutoff value for disease activity was 15.5 in comparison with the BDCAF with high area under the curve 0.972 at 95% confidence interval (CI) on the receiver operating characteristic curve (ROC). Conclusions: The Arabic version of the BSAS (Ar- BSAS) is a reliable, valid, and accurate patient reported measure for disease activity that could be used to evaluate disease activity and enhance the therapeutic management choices in routine clinical practice.