Objective: To evaluate the antimalarial and antioxidant properties of stem bark extracts of Haematostaphis barteri (H. barteri). Methods: The prophylactic activity of the plant was performed by dosing mice with sulfadoxine-pyrimethamine (1.2 mg/kg), aqueous extract (30, 100, 300 mg/kg) and dichloromethane/methanol (D/M) (30, 100, 300 mg/kg) extracts of H. barteri for 3 days. On the 4th day, the mice were inoculated with Plasmodium berghei. The parasite density was estimated for each mouse 72 h post-parasite inoculation. The curative activity of the plant was also performed by inoculating mice with Plasmodium berghei. Three days later, they were treated with artemether-lumefantrine (4 mg/kg), aqueous and D/M extracts of H. barteri stembark for 5 days. The in vitro antioxidant property of the aqueous extractwas determined by using the reducing power, nitric oxide and total antioxidant capacity assays. Results: The aqueous extract exerted significant (P < 0.05) curative and prophylactic antimalarial activities. The D/M extract exhibited significant curative (P < 0.05) but not prophylactic antiplasmodial effect. The aqueous extract exhibited in vitro antioxidant property with IC