Introduction: Skin aging is a multifactorial process caused by chronological changes and environmental factors. Green tea, a processed tea plant (Camellia sinensis (L) Kuntze), possesses health benefits and has been used in traditional medicines and natural products. However, the anti-skin aging effect of green tea in clinical trials has been a controversial issue. To clarify this without the interference of systemic involvement, the objectives of study were to investigate the activities of green tea against skin aging in B16F10 melanoma cells and human skin fibroblasts. Methods: Green tea leaves were extracted to standardise the phenolic profile. The cytotoxicity and the anti-skin aging activities, including melanogenesis assay, antioxidant activity, collagen content analysis, and matrix metalloproteinase-2 inhibitory assay, were evaluated in cell culture. Results: Green tea in this study composed mainly of epigallocatechin gallate (1,903.77 ± 33.59 μg/mL), epigallocatechin (930.24 ± 27.04 μg/mL), and epicatechin gallate (607.84 ± 22.65 μg/mL). The cell viabilities of 0.5 % (0.0875 mg/mL) green tea, the noncytotoxic concentration, were 96.04 ± 6.76 and 93.44 ± 0.95 % in B16F10 melanoma cells and human skin fibroblasts, respectively. Green tea exhibited the activities against skin aging, including the significant suppression of melanin production via inhibition of tyrosinase and tyrosinaserelated protein-2 activities, the potent antioxidant, and the significant matrix metalloproteinase-2 inhibition (p < 0.001). Conclusions: The study results have shown that green tea may be a functional processed plant which could be used as an anti-skin aging agent in natural remedies, including food, health, and cosmetic products.