Introduction Melanoma is a malignant tumour and is the leading cause of death in patients with skin tumours. Aim Kaempferol belongs to a class of flavonoids, and is associated with many biological functions such as anti-inflammatory, anti-oxidation and anti-cancer. However, the inhibitory effect of kaempferol on melanoma still remains unclear. Material and methods The effect of kaempferol on melanoma was determined by conducting both in vitro and in vivo experiments using MTT assay and flow cytometry. Results The in vitro results revealed that kaempferol obviously inhibited cell viability of melanoma B16 cells, induced cell cycle arrest and cell apoptosis. The in vivo results showed that kaempferol effectively inhibited the growth of mice xenografts. More importantly, kaempferol down-regulated the number of MDSC cells and up-regulated the number of NKT cells and CD8 T cells in the spleen. Conclusions Taken together, these findings indicate that kaempferol might play an inhibitory role in the growth of melanoma by enhancing anti-tumour immunity of organisms.