Introduction: Caryota urens belongs to the palm family and is widely distributed in Asia. Conventionally, it is used to treat gastric ulcers, snake bites, migraine, and rheumatic swellings. The objectives of this study were to determine the phytochemical content and antioxidant activities of hydroalcoholic and aqueous (Aq) extracts of various parts of C. urens. Materials and Methods: Extractions of various parts of C. urens were performed by cold maceration using different solvents such as 70% ethanol and distilled water. The extracts were subjected to assessment of their antioxidant potential using various in vitro systems such as 1,1-diphenyl-2-picrylhydrazyl radical, hydroxyl radical, superoxide radical, lipid peroxidation, and phosphomolybdenum reduction. The extract was subjected to Fourier-transform infrared spectroscopy, liquid chromatography–mass spectrometry (LC-MS), and high-performance liquid chromatography (HPLC) analysis to detect the phytoconstituents. Results: The total flavonoid and total phenol content was found to be highest in leaf hydroalcoholic extract (C. urens leaf hydroalcoholic extract [CULHA]), 43.84 ± 3.59 mg/g quercetin equivalent, and 41.68 ± 3.30 mg/g gallic acid equivalent, respectively. Hydroalcoholic extracts of C. urens (CULHA, C. urens fruit hydroalcoholic extract and C. urens bark hydroalcoholic extract) had the highest antioxidant activity when compared to Aq extracts. Phenolic acids, coumarins, carboxylic acids, and flavonoids were characterized by LC-MS. HPLC analysis further confirmed the presence of rutin, umbelliferone, and ferulic acid. Conclusion: A direct association between the high content of flavonoid rutin and antioxidant activity in leaf hydroalcoholic extract was noted. The fact that C. urens is rich in coumarins and rutin seems to explain the high antioxidant potential of this plant extract.