Non Sombun (Thai: โนนสมบูรณ์) is a tambon (subdistrict) located in the southern region of Det Udom District, in Ubon Ratchathani Province, Thailand. In 2021, it had a population of 5,993 people. Neighbouring subdistricts are (clockwise from the south) Kaeng, Na Kasem, Som Sa-at, Tha Pho Si, and Top Hu.

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

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.

The Non Sombun subdistrict is divided into nine administrative villages (mubans; หมู่บ้าน). The entire area is governed by the Subdistrict Administrative Organization of Non Sombun (องค์การบริหารส่วนตำบลโนนสมบูรณ์; Non Sombun SAO).

As of the 2021 census, it had a population of 5,993 people with 2,066 households. The following is a list of the subdistrict's mubans, which roughly correspond to the villages.

Village		Group (Mu)	Household	Population
Romanized name	Thai name
Na Udom	นาอุดม	1	285	964
Na Khae	นาแก	2	297	804
Mai Pattana	ใหม่พัฒนา	3	252	688
Than Wela Samakkhi	ทันเวลาสามัคคี	4	126	393
Non Sombun	โนนสมบูรณ์	5	399	906
Kha-nuan	ขนวน	6	140	482
Suan Sawan	สวนสวรรค์	7	203	529
Khok Khlang	กอกกลาง	8	97	389
Non Ngam	โนนงาม	9	267	838
Total			2,066	5,993

14°46′06″N 105°02′26″E / 14.768273°N 105.040589°E / 14.768273; 105.040589