Non Sombun (Thai: โนนสมบูรณ์) is a tambon (subdistrict) located in the southern region of Det Udom District, in Ubon Ratchathani Province, Thailand.

[1] Neighbouring subdistricts are (clockwise from the south) Kaeng, Na Kasem, Som Sa-at, Tha Pho Si, and Top Hu.

[2] The tambon was formed in 1993, by splitting off nine villages in the northern region of Kaeng.

[3] After its establishment, the tambon was governed by the Subdistrict Council of Non Sombun until February 20, 1997, when the council was upgraded by the Department of Provincial Administration [th] to be the Subdistrict Administrative Organization of Non Sombun.

[2] The tambon is located in the southern region of the Det Udom district, on the undulating land alongside the low river plain of the Lam Dom Yai River, with a tropical savanna climate.