Sour orange (Citrus aurantium L.), which belongs to the Rutaceae family, is used around the Mediterranean Sea for ornamental and agronomic purposes as a rootstock for the Citrus species. Peels and flowers, the most-used parts of Citrus aurantium L., have constituted a largely promising area of research for their many medicinal properties. However, the leaves of sour orange have not yet been studied extensively. The present study aimed at investigating the essential oil composition of sour orange leaves grown in Algeria and determining their antioxidant and anti-inflammatory properties. Essential oil composition of leaves harvested before flowering was determined by GC-MS. Total phenol content, antioxidant activities (DPPH) and elastase and collagenase inhibition were assessed. Forty-three volatile compounds were detected in essential oil from leaves with a yield of 0.57%. The major compounds were linalool, linalyl acetate and α-Terpineol. Results show that the total phenol content and antioxidant activity of essential oil are low, 3.48 ± 0.10 mg/g (Gallic Acid Equivalent/EO) and IC50 > 10,000 mg·L−1, respectively. In contrast, EO present an interesting level of elastase and collagenase inhibition. This result emphasizes the potential interest of the essential oil of sour orange mainly in relation to its anti-aging mechanism.