Na Muean (Thai: นาหมื่น, pronounced [nāː mɯ̀ːn]) is a district (amphoe) in the southern part of Nan province, northern Thailand.

The minor district (king amphoe) Na Muean was established on 9 October 1978 as a subordinate of Na Noi district, from which it was split off.

[1][2] Originally it consisted of the three tambons, Na Thanung, Bo Kaeo, and Mueang Li.

[3] Neighboring districts are, from the north clockwise, Na Noi of Nan Province, Ban Khok, Fak Tha, Nam Pat and Tha Pla of Uttaradit province, Mueang Phrae and Rong Kwang of Phrae province.

The district is divided into four sub-districts (tambons), which are further subdivided into 48 villages (mubans).