Skin hyperpigmentation is a common disorder often associated with various diseases. Melanogenesis is the formation of pigment called melanin in the cells of skin. This process primarily requires the amino acids tyrosine and L-DOPA (3,4-dihydroxyphenylalanine). Consequently, many skin-whitening cosmetics aim to inhibit melanin formation by targeting tyrosinase activity or scavenging L-DOPA. In this study, the brown seaweed Hormophysa cuneiformis, collected from Hurghada, Red Sea, Egypt, was investigated for its anti-melanogenic potential through its methanolic extract. The potential of antioxidant in the algae-derived solution was found to be 2.8mg/ g dry weight comparable to ascorbic acid. Phytochemical analysis revealed a total phenol content of 1.87mg/ g dry weight comparable to gallic acid. The flavonoid composition was found to be 0.86mg/ g dry weight comparable to rutin. The anti-melanogenic potential of Hormophysa cuneiformis extract was estimated by assessing its cytotoxic impact on the viability of B16F1 melanoma cells via MTT assay using different concentrations compared to kojic acid. Additionally, the inhibition of α-melanocyte stimulating hormone (α-MSH) was analyzed following addition of different doses of the algal extract. The results demonstrated that the algal extract suppressed both extra and intra-cellular activity of tyrosinase in melanoma cells. The intracellular tyrosinase suppression was further confirmed by zymography, which analyzed the expression level of tyrosinase as a protein compound. In conclusion, this study strongly suggests that Hormophysa cuneiformis extract possesses significant anti-melanogenic activity, making it a promising candidate for development as a novel natural cosmeceutical compound for skin whitening.