Cajanus cajan (aka pigeon pea) is a terrestrial medicinal plant native to Asian and African countries before being introduced to the American continent. This protein-rich legume species, belonging to the Fabaceae family, has been traditionally used to cure various ailments in many traditional medicines. Recent works have highlighted it as a rich source of a wide array of flavonoids and other phenolic compounds. The major biological activities that are currently reported on are mainly focused on antioxidant and anti-inflammatory activities which are relevant for the cosmetic field. For example, hydroalcoholic extract from C. cajan has been highlighted as a particularly effective antioxidant in various scavenging assays for both reactive oxygen or nitrogen species. One of its constituents, cyanidin-3-monoglucoside, has been reported to suppress inflammatory cytokine production (e.g., TNF-α, IL-1β, and IL-6 in murine RAW264.7 macrophages). The present review provides an overview on the flavonoids and phenolics from C. cajan as well as their biological activities that can be applied for cosmetic applications. In addition, the botanical data including taxonomic description, flowering season, distribution, synonyms and traditional uses are illustrated, so as to provide an overview of pigeon pea’s cosmetic/cosmeceutical potentials.