Based on original ethnographic and ethnobotanical research, we share how in the cosmology of Tanna, an island in Vanuatu’s southernmost province of Tafea, the Sun is viewed as a living, interactive being. Our initial interviews explored knowledge and beliefs concerning individual plant species, then subsequent follow-up interviews further explored topics that emerged therefrom. The results of these interviews are a series of oral narratives of the mytho-historical past involving the Sun, and the description of contemporary practices which are influenced by the Sun. In traditional narratives, the Sun is both a creative and destructive force which is sometimes viewed as an active, personified character, and in other circumstances appears as an instrument created and utilized by greater powers. People from Tanna recount—and we adopt as a hypothesis—that the Sun’s physical manifestation and role in the world has changed since the earliest days of its mythological creation, and that it remains an active player in Tanna’s biocultural landscape within practices including time-reckoning, agriculture, and architecture. Through its relationships with humans and non-humans alike, the Sun ultimately shapes the cultural practices and even the landscape of Tanna. The nature of these relationships is changing as linguistic and cultural practices shift alongside people’s relationship with the land, but the Sun remains a critical factor in lives and livelihoods of Tanna today.