Crataegus azarolus, or Mediterranean hawthorn, is native to southern Europe, North Africa, North America, and the Middle East. In Tunisia, it grows mainly in the mountainous northwest under a Mediterranean climate. Its fruits and leaves are prized for their nutritional and medicinal benefits. However, little research has explored how bioclimatic factors affect its biochemical and morphological traits. This study investigated Crataegus azarolus var. aronia L., focusing on its morphological traits and biochemical composition across four bioclimatic zones in Tunisia: upper humid, lower humid, upper semi-arid, and lower semi-arid. Morphological descriptors and water content were first measured, after which fresh and dried samples underwent biochemical analyses. Methanolic extracts of leaf and fruit powders were analyzed to assess phenolic content and antioxidant activity. The results showed that environmental conditions had a limited effect on fruit and seed morphology, water content, primary metabolites, and flavonoid levels. However, leaf morphology was significantly influenced, with the lower humid zone exhibiting the highest number of leaves per bouquet (8.07 +/- 0.641) and the upper semi-arid zone showing the longest internodes (1.00 +/- 0.131 cm). Vitamin concentrations peaked in the upper humid zone (29.182 +/- 2.01 mg/100 g fresh matter), while polyphenol content was highest in the lower humid zone for leaves (148.04 +/- 3.2 GAE mg/g dry matter) and in the lower semi-arid zone for fruits (142 +/- 2.7 GAE mg/g dry matter). Tannin content reached its maximum in the lower semi-arid zone. Antioxidant activity, measured by reducing power, was highest in leaves from the upper humid zone (845.751 mg/100 g dry matter) and fruits from the upper semi-arid zone (844.411 mg/100 g dry matter). These findings underscore the critical role of bioclimatic factors in shaping the biochemical properties of C. azarolus var. aronia L. and highlight its potential for applications in food, pharmaceutical, and nutraceutical industries.