To examine the potential of Terminalia chebula as a whitening agent, we measured antioxidant activity using DPPH$cdot$, ABTS${cdot}^+$ assays and ferric-reducing antioxidant power (FRAP) assays, and depigmenting activity using B16F10 melanoma cells. The intracellular reactive oxygen species (ROS) level was monitored by $H_2DCFDA$ fluorescence labeling, and melanin contents in B16F10 melanoma cells by 960 $J/m^2$ dose of UVA-induced oxidative stress. The radical-scavenging activities of T. chebula extract (TCE) were measured in terms of $EC_{50}$ values using DPPH$cdot$, ABTS${cdot}^+$ assays and FRAP value were 280.0 ${mu}g/mL$, 42.2 ${mu}g/mL$ and 113.1 ${mu}mol$ $FeSO_4{cdot}7H_2O/g$, respectively. We found that ROS and melanin concentrations were reduced by TCE treatments of 25 ${mu}g/mL$ under UVA-induced oxidative stress. Tyrosinase activity and melanin contents in $alpha$-melanocyte stimulating hormone (MSH)-induced melanoma cells both decreased dose-dependently in the treatment groups. TCE similarly reduced melanogenesis in B16F10 melanoma cells stimulated by $alpha$-MSH as compared to arbutin as a positive control. T. chebula may prove to be a useful therapeutic agent for hyperpigmentation and an effective component in skin whitening and.or lightening cosmetics.