The current study aimed to investigate the preliminary phytochemical screening, quantify the total phenolic (TPC), flavonoidal (TFC) contents and evaluate the antioxidant activities of the total methanol extract (ME) of the aerial parts and its derived fractions of Lolium perenne L. (L. perenne). The preliminary phytochemical screening of ME displayed the presence of carbohydrates and/or glycosides, steroids and/or triterpenes, phenolic compounds, proteins and/or amino acids, flavonoids, and quinones. Dichloromethane (DFr) and ethyl acetate (EFr) fractions showed the highest TPC (82.42±2.70 and 70.85±2.27 mg gallic acid equivalent (GAE)/g dried sample), respectively. Also, DFr and EFr displayed the highest TFC (115.65±6.43 and 146.00±1.06 mg rutin equivalent (RE)/g dried sample), respectively. All samples showed variable antioxidant properties. While EFr, followed by DFr, demonstrated the least IC50 value of 120.04±0.43 and 166.81±0.53 µg/mL, respectively, indicating their high antioxidant potential.