Triumfetta cordifolia is a medicinal plant that has been widely utilized in Africa for its therapeutic properties in treating various ailments. The purpose of this research was to investigate phytochemicals and in vitro antioxidant activity of the leaf extract of T. cordifolia. Standard methods were employed to conduct qualitative phytochemical screening of the plant extract. This study used the DPPH (1, 1diphenyl-2-picryl hydrazyl) radical scavenging and ferric reducing antioxidant power method to assess antioxidant activity. Phytochemical analysis of T. cordifolia leaves indicated the existence of saponins, tannins, terpenoids, cardiac glycosides, alkaloids, flavonoids but no anthraquinones. In the DPPH scavenging test, the IC50 value of the methanolic extract was discovered to be 1.29 µg/mL, and the standard reference value for ascorbic acid was 2.14 µg/mL. The leaf extract of T. cordifolia displayed stronger inhibition of DPPH activity, showing a higher potency than ascorbic acid. The DPPH scavenging activity was also shown to increase with concentration. In FRAP assay, the T. cordifolia leaf extract and the ascorbic acid revealed reducing power of 71.01±0.15 and 548.39±1.62 μM Fe2+ per mg of extract, respectively. The FRAP assay demonstrated that ascorbic acid exhibited greater antioxidant activity than the leaf extract of T. cordifolia. The presence of flavonoids and phenols in T. cordifolia leaves may account for the observed antioxidant activity. In conclusion, the study's findings suggest that that T. cordifolia leaf extract could be a source of lead compounds with promising antioxidant activity.