Antioxidant capability, total phenolic contents and total flavonoids of various solvent extracts of Ziziphora clinopodioides aerial parts from three geographical locations of Iran were evaluated in this work. Antioxidant activities of the samples were determined by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay. The aqueous methanol extract from Lar region exhibited the greatest antioxidant capacity (IC50=91.27±1.89 μg/mL) than that of other extracts (ethanol and methanol), which was probably due to its high content of polyphenols (78.74±1.17 mg gallic acid equivalent/g dry extract). The ethanol extracts of three population of the plant has been found to be rich in flavonoids. There was a correlation between the antioxidant activity potential and amount of phenolic compounds in all extracts. The observed differences in antioxidant activity of Ziziphora clinopodioides extracts could be attributed to the variations of composition in the polyphenol contents of the plant grown in different geographical locations due to diverse environmental or climatic factors.