Nong Om (Thai: หนองอ้ม) is a tambon (subdistrict) located in the northernmost area of Thung Si Udom district, in Ubon Ratchathani Province, Thailand.

[2] The tambon Nong Om was formed in 1969, by splitting off 10 villages in the southeastern region of Thung Thoeng in Det Udom district.

[3] Later in 1991, the southwestern region of the tambon, which consisted of eight villages, was cut off to establish a new division, Khok Chamrae.

[4] A year after the demarcation, both Nong Om and Khok Chamrae, together with three other subdistricts, including Thung Thoeng, Na Kasem, and Kut Ruea, were split off from Det Udom district to create a minor district (king amphoe) called Thung Si Udom.

[6] The tambon is located in the northern region of the Thung Si Udom district, on the undulating land between the low river plains of the Lam Dom Yai River (ลำโดมใหญ่) in the east and of the Huai Khayung Creek (ห้วยขะยุง) in the west.