The Nommo or Nummo are primordial ancestral spirits in Dogon religion and cosmogony venerated by the Dogon people of Mali. The word Nommos is derived from a Dogon word meaning "to make one drink." Nommos are usually described as amphibious, hermaphroditic, fish-like creatures. Folk art depictions of Nommos show creatures with humanoid upper torsos, legs/feet, and a fish-like lower torso and tail. Nommos are also referred to as "Masters of the Water", "the Monitors", and "the Teachers". Nommo can be a proper name of an individual or can refer to the group of spirits as a whole. For purposes of this article, "Nommo" refers to a specific individual and "Nommos" is used to reference the group of beings.

The Dogon are an ethnic group indigenous to the central plateau region of Mali, in West Africa, south of the Niger bend, near the city of Bandiagara, and in Burkina Faso. The population numbers between 400,000 and 800,000. They speak the Dogon languages, which are considered to constitute an independent branch of the Niger–Congo language family, meaning that they are not closely related to any other languages.