The composition of the essential oils obtained from the air-dried Teucrium chamaedrys L. subsp. chamaedrys, Teucrium orientale L. var. puberulens, and Teucrium chamaedrys L. subsp. lydium ( Lamiaceae) were analyzed by GC-MS. Thirty-six, 35, and 33 components were identified in the essential oils, and germacrene D (16.7%) was the most abundant constituent in T. chamaedrys subsp. chamaedrys, and beta-caryophyllene was the most abundant component in both T. orientale var. puberulens and T. chamaedrys subsp. lydium in the ratios 21.7% and 19.7%, respectively. The isolated essential oils of the plants were tested for antimicrobial activity and showed moderate antibacterial activity against Gram-positive and Gram-negative bacteria, but no antifungal activity was observed against two yeast-like fungi.