Non Sa-at (Thai: โนนสะอาด, pronounced [nōːn sāʔàːt]) is a district (amphoe) in the southern part of Udon Thani province, northeastern Thailand.

Neighboring districts are (from the north clockwise) Nong Saeng and Kumphawapi of Udon Thani Province, Kranuan, Nam Phong, and Khao Suan Kwang of Khon Kaen province.

The minor district (king amphoe) was established on 21 January 1974, when the three tambons, Non Sa-at, Pho Si Samran, and Bung Kaeo, were split off from Kumphawapi district.

[2] The district is divided into six sub-districts (tambons), which are further subdivided into 63 villages (mubans).

Non Sa-at is a source for growing mulberries and raising sericulture to produce good quality Thai silk.