Ultraviolet (UV) radiation is a prime environmental stressor that our epidermis is exposed to on a daily basis. To avert UV-induced damage, epidermal stem cells (EpSCs) become pigmented via a process of heterotypic interaction between melanocytes and EpSCs; however, the molecular mechanisms of this interaction are not well understood. In this study, we show that the function of a key chromatin regulator, the Polycomb complex, was reduced upon UV exposure in human and mouse epidermis. Genetic ablation of key Polycomb subunits in murine EpSCs, mimicking depletion upon UV exposure, results in an increased number of epidermal melanocytes and subsequent epidermal pigmentation. Genome-wide transcriptional and chromatin studies show that Polycomb regulates the expression of UV-responsive genes and identifies type II collagen (COL2A1) as a critical secreted regulator of melanogenesis and epidermal pigmentation. Together, our findings show how UV exposure induces Polycomb-mediated changes in EpSCs to affect melanocyte behavior and promote epidermal pigmentation. Display omitted •Polycomb repression is reduced in the epidermis upon low-dose UV exposure•Loss of Polycomb repression in the epidermis results in epidermal pigmentation•Polycomb controls epidermal pigmentation via a p53-independent pathway•Type II collagen promotes UV-induced epidermal pigmentation Li et al. demonstrate that low-dose UVB exposure leads to a drastic reduction in Polycomb levels in the epidermis. Furthermore, ablation of Polycomb function in the epidermis results in epidermal pigmentation via a p53-independent pathway. They identify Polycomb-regulated protein, type II collagen, as a critical regulator of melanogenesis.