Asthma is a prevalent chronic respiratory disease associated with significant morbidity and mortality globally. Effective self-management of asthma depends on adequate numeracy skills, which are essential components of health literacy (HL). Although the Asthma Numeracy Questionnaire (ANQ) has been validated among parents of asthmatic children, no previous studies have specifically validated the tool among adult patients with asthma. Therefore, this study aimed to validate the Arabic version of the Ar-ANQ among adult patients with asthma in Jordan, assess their asthma-related numeracy skills, and identify demographic and clinical factors associated with numeracy. A cross-sectional study was conducted with 398 adult patients with asthma attending the Respiratory Therapy Unit at the University of Jordan Hospital (JHU) from November 2024 to April 2025. Participants completed the Arabic Ar-ANQ and provided demographic information. The questionnaire's validity and reliability were evaluated using Confirmatory Factor Analysis (CFA) and Rasch analysis. Associations between Ar-ANQ scores and sociodemographic variables were analyzed using quantile regression. Confirmatory Factor Analysis (CFA) confirmed the unidimensional structure of the Ar-ANQ (SRMR = 0.02, CFI = 0.98, GFI = 0.99, TLI = 0.95), demonstrating high internal consistency (Cronbach's α = 0.80). Rasch analysis further supported the instrument's reliability, with acceptable infit and outfit statistics, as well as item and person separation reliability indices. Numeracy skills varied significantly among participants, influenced by education level and income, with higher Ar-ANQ scores observed among those with higher educational attainment and income levels. The Ar-ANQ is a valid and reliable instrument for evaluating numeracy skills essential for effective asthma self-management among adult asthmatic patients. Its use can facilitate targeted educational interventions and improved asthma control.