Cuscuta pentagona Engelm. (Cuscutaceae), a parasitic plant traditionally used in Syria for treating liver disorders and skin infections, remains phytochemically and pharmacologically underexplored. This study aimed to investigate the phytochemical composition and in vitro antioxidant potential of its aerial parts and fruits. Plant materials were collected from northeastern Syria, and extracts were prepared using 70% ethanol via maceration. Preliminary phytochemical screening of the aerial parts confirmed the presence of flavonoids and coumarins, while revealing the absence of saponins, anthraquinones, tannins, alkaloids, and cardiac glycosides. Quantitative analyses demonstrated that the aerial parts extract possessed significantly higher total phenolic and flavonoid contents (45.00 ± 0.041 mg GAE/g and 24.30 ± 0.033 mg QE/g dry weight, respectively) compared to the fruit extract (23.50 ± 0.080 mg GAE/g and 9.09 ± 0.047 mg QE/g). Consistent with this chemical profile, the aerial parts extract exhibited superior free radical scavenging activity in the DPPH assay, with an IC₅₀ value of 64.00 ± 0.380 µg/mL, markedly lower than that of the fruit extract (168.70 ± 0.474 µg/mL). The results strongly indicate that the aerial parts of C. pentagonaare a rich source of phenolic antioxidants, primarily flavonoids, which contribute to its significant radical scavenging capacity. This provides a scientific basis for its traditional use and underscores its potential as a source of natural antioxidant compounds.