The present study investigated the compositional variation and antioxidant potential of Origanum vulgare L. (subsp. vulgare) collected from three districts of Uttarakhand, India. The essential oil composition was analyzed by GC and GC/MS, and the antioxidant potential was evaluated using 2,2Ê¹-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, ferric reducing antioxidant power (FRAP) activity and Fe2+-ferrozine test system for iron-chelating activity methods. The analysis allowed the identification of 22â36 compounds representing 87.84â92.95% of the total essential oil. Samples S1 and S2 contained a high amount of sesquiterpene hydrocarbons (26.37â47.25%), while sample S3 was rich in oxygenated monoterpenes (70.21%). The major component was (E)-caryophyllene in S1 and S2 samples (15.40â26.41%) and thymol (60.3%) in S3 sample. The S3 sample collected from the lowest altitude showed the highest oil yield and antioxidant activity.