In the present investigation, leaves of Terminalia muelleri were assayed for their phytochemical constituents, as well as its free radical scavenging activity. The antioxidant effect was measured using 2,2-diphenyl-1-picrylhydrazyl (DPPH^•) radical scavenging assay, the phytochemical constituents were screened to assess their corresponding effect on antioxidant activity. The results showed that the ethanol soluble fraction of T. muelleri possesses a potent radical-scavenging activity using the DPPH^• (2,2-diphenyl-1-picrylhydrazyl) radical-scavenging assay (IC₅₀ value = 2.7 μg/mL, while the standard ascorbic acid has an IC₅₀ value = 10.5 μg/mL).