In Uganda, the Teso live mainly in Teso sub-region, i.e., the districts of Amuria, Soroti, Kumi, Katakwi, Ngora, Serere, Pallisa, Bukedea and Kaberamaido, as well as in the districts of Tororo and Busia. They number about 3.2 million (9.6% of Uganda's population). Until 1980, they were the second largest ethnic group in Uganda. As of 2002 they were the fifth largest but this has remained questionable especially since there has never been any genocide that could have massacred more than a half of the Iteso populace. Most of the Iteso therefore contend that they are still the second largest ethnic group in Uganda. In fact the figure portrayed by UBOS is rather a political statement than an accurate recording of the Iteso in Uganda. Most Teso elites continue to argue that, since the national budget is disbursed based on population numbers, some individuals in government often manipulate these figures to suit their political interests and as such, as long as the current NRM government continues in power, the national population census figures can never be accurate but rather will continue to serve selfish political interests in order to justify why some areas in the Country like Teso, remain poor and underdeveloped. 
Northern and Southern Teso
Teso traditions relate that they originated somewhere in what is now Egypt in the area of Alexandra. They are believed to have descended from the Hebrew Joseph who had married a black Egyptian. Later when the Israeli slaves left Egypt for the promised land, the group followed the blue Nile river into Ethiopia. It is from here that they obtained the name Iteso, meaning we have seen. They saw a land, part of the promise to Jacob, the grand son of Abraham, it is a land divided by small rivers originating from the White Nile, theirs was the Upper Nile area. From the Ethiopian mountains is where they saw the land. They later migrated south West over a period of centuries. They were part of a larger group of Nilo-Hamitic peoples who include; the Masai and Turkana of Kenya, the Nyangatom of present day Ethiopia, Karamojong, the Topotha of South Sudan, all are they Ateker. The Ateker further split into several groups, including Jie, Turkana, Karamojong and Teso.
The Teso established themselves in present-day north-eastern Uganda, and in the mid-18th century some began to move farther south. During the course of this latter migration, conflicts ensued with other ethnic groups in the region, leading to the split of Teso territory into a northern and southern part. In 1902, part of eastern Uganda was transferred to western Kenya - leading to further separation of Teso.
Northern Teso occupy the area previously known as Teso District in Uganda (now the districts of Amuria, Soroti, Kumi, Katakwi, Pallisa, Bukedea and Kaberamaido). Southern Teso live mainly in the districts of Tororo and Busia in Uganda, and Busia District in Kenya's Western Province.
- Karp, Ivan (1978). Fields of Change among the Iteso of Kenya. Routledge; Reprint edition (2005). ISBN 0-415-32990-6.
- 2002 Uganda Population and Housing Census: Analytical Report (Uganda Bureau of Statistics)
- Ethnologue: Teso
- Mwakikagile, Godfrey (2009). Ethnicity and National Identity in Uganda: The Land and Its People. New Africa Press. ISBN 9987-9308-7-5.
- Shillington, Kevin (2005). Encyclopedia of African History Volume 1 A-G. New York: Routledge. pp. 1912 pages. ISBN 1-57958-245-1.