Teff belongs to the Grass or Poaceae Family (formerly Gramineae), sub‐family Chloridoideae, tribe Eragrostideae and genus Eragrostis and species Eragrostis tef (Zucc.) Trotter. The genus contains about 300 species. The word ‘teff’ originates from the Amharic word ‘teffa’ which means ‘lost’ due to the small size of the grain or from the Arabic word ‘tahf’ used by the Semites in South Arabia. The word ‘teff’ comes from the Ethiopian word ‘teffa’, which means ‘lost’ because of its minute grain size. Teff grains are manually harvested by sickles and threshed with ox tramping on them. It was estimated that 25-30% of teff would be lost before and after harvest, and lodging may contribute to the yield loss up to 30%. The high losses along the production processes can reduce the available quantity of teff by up to 50%. Common names of Eragrostis tef (Zucc.) Trotter in English are Tef, Teff, Teff grass, Williams lovegrass, Abyssinian lovegrass, Lovegrass, Annual Bunch Grass, Warm Season Annual Bunch Grass. Also written as: Ttheff, Tteff, Thaff, Tcheff, Thaft, Tcheff. It is also known by the vernacular names tafi in Oromigna and taf in Tigrigna. The species in the genus Eragrostis generally range from diploid (2x = 2n = 20) to hexaploid (2x = 6x = 60). Tef is an allotetraploid species (2n = 4x = 40) originating from the hybridisation of two distinct species followed by diploidisation. Tef (Eragrostis tef (Zucc.) Trotter) is a crop for which Ethiopia is the center of origin and diversity. Tef is endemic to Ethiopia and its major diversity is found only in this country. Tef is a fine grain that comes in a variety of colors, from white and red to dark brown. The exact date and location for the domestication of tef is unknown, it is native and an important cereal crop to Ethiopia which is believed to be originated between 4000 and 1000 BC. However, there is no doubt that it is a very ancient crop in Ethiopia, where domestication took place before the birth of Christ. Teff grain is the smallest of all whole flour grains in the world with a length of about 1.0 mm and a width of about 0.60 mm. The average thousand grain weight of teff kernels is only 0.26 g. The grain color ranges from a light ivory to very dark reddish brown depending on the variety. However, when the whole grain is finely ground, the difference in flour color becomes less noticeable. This may indicate that the pigmenting compounds of the brown teff grains are mainly accumulated on the grain pericarp. Ethiopians primarily use teff to make their national dish known as ‘’injera’’. Injera is a type of sourdough-risen flatbread which looks like a flat pancake with a unique sponge-like texture. Traditionally it is eaten with a range of different toppings such as stews, salads or sauces. However, like a pancake, there are a great number of ways and possible toppings to eat injera with. Teff is a labour-intensive crop and requires significant soil preparation to ensure even sowing and proper seed depth. Additionally, harvesting, threshing, and winnowing are often done by hand, and the tiny seeds are tedious to handle and transport without loss. Regarding cultivation “Teff” need special attention in contrast to other crops. Indigenous knowledge practiced by farmers were shown the preparation of farmland, weeding time and style, harvesting time and style, why pilled after harvest, preparation of “Awudima” for threshing and the purpose of grain stored. Ethiopian farmers were inherited this indigenous knowledge from their families (father and grandfather) and local communities. In Ethiopia, farmers’ indigenous knowledge on “Teff” production and management system were immemorially practiced. Ethiopian mothers and consumers obviously prefer and accordingly pay higher price for “Teff” grain stored for long period. They were mentioned that the qualities of such grain for making “Injera”. In conclusion, “Teff” grain most commonly is consumed after being stored for several months and only a rare case or in critical food problem that it would be used immediately after harvest. This indigenous knowledge has already been inherited from their families for several generations. Respondents and many generations of farmers before them, have always harvested, put sheaves of “Teff” on the farmland “Dekel”, pilled “Zememen” and finally pilled “Teff” at threshing site. In this review article on Origin, Domestication, Taxonomy, Botanical Description, Genetics and Cytogenetics, Genetic Diversity, Breeding, Uses, Nutritional Value and Health Benefits of Teff or Ethiopian Millet are discussed.