Oyamatsumi-no-okami is a mountain deity (kami) in Shinto tradition, regarded as a foundational spirit governing mountains and the natural landscape. According to the Kojiki and Nihon Shoki, he is counted among the offspring of the primal creator deities Izanagi and Izanami, and is often venerated as an ancestral figure connected to mountains, seas, and the fertility of the land. He is honored at shrines such as Oyamazumi Shrine on Omishima Island, where he is associated with mountains, seafaring, and agriculture, reflecting the reverence shown to natural forces in Shinto practice.