The essential oil of hyssop is widely used in food, pharmaceutical and cosmetic industries throughout the world. Therefore, it is very important to know the chemical characteristics of the oil for economic use and enhanced performance of the end products. This study was carried out to determine antimicrobial and antioxidant activities of the essential oil of Hyssopus officinalis (L.) (Lamiaceae) collected from wild in the Southeast Anatolian, Turkey. Chemical compositions of hydrodistilled essential oils obtained from hyssop leaves were analyzed by gas chromatography-mass spectrometry (GC-MS). For antimicrobial activity, disc diﬀusion tests were carried out on Escherichia coli line ATCC25922, Pseudomonas aeroginosa line ATCC27853, Staphylococcus aureus line 25923, Staphylococcus pyogenes line ATCC19615 and Candida albicans line ATCC10231, and the antioxidant activity was determined by using the diphenylpicrylhydrazyl (DPPH) radical-scavenging method. It was determined that hyssop essential oil contained isopinocamphone (57.27%), (-)-β-pinene (7.23%), (-)-terpinen-4-ol (7.13%), pinocarvone (6.49%), carvacrol (3.02%), p-cymene (2.81%) and myrtenal (2.32%) as major components. As shown by treatments with 5 and 10 μl of oil; which exhibited strong antimicrobial activity against S. pyogenes, S. aureus, C. albicans and E. coli, but not against P. aeruginosa. Te antioxidant activity of H. officinalis essential oil was lower compared to butylated hydroxytoluene (BHT) and ascorbic acid. Tese results demonstrated that hyssop essential oil has relatively low antioxidant activity and good antimicrobial activity against some test organisms.