The composition and antibacterial activity of the essential oil of the aerial flowering parts of Nepeta hormozganica Jamzad have been studied. Analysis of the oil was conducted by GC-FID and GC-MS. Thirty-two components were characterized accounting for 99.4% of the total oil. Oxygenated monoterpenes (87.5%) were found to be the predominant group of compounds, of which 18-cineole (65.0%) and 4aα-7α-7aβ-nepetalactone (13.0%) were the main constituents. The antibacterial activity of the essential oil and its main constituents showed that all of the tested microorganisms were highly inhibited by the essential oil with inhibition zones ranged from 12 to 24 mm. The most sensitive bacteria were Staphylococcus aureus and Staphylococcus epidermidis with the lowest MIC values of 0.3 and 0.6 mg/mL, respectively. Considering sensitivity screening it is conceivable that the activity of the oil from N. hormozganica could be attributed mainly to the synergistic property of 18-cineole and nepetalactone.