Mueang Roi Et (, ; , ) is the capital district (amphoe mueang) in the western part of Roi Et province, northeastern Thailand.
Mueang Roi Et is an ancient city. The area around the city was made into a district in 1908. In 1913 its name was changed from Pachin Roi Et to Mueang Roi Et.
Neighboring districts are (from the north clockwise): Changhan, Chiang Khwan, Thawat Buri, At Samat, Mueang Suang (at a single point), Chaturaphak Phiman and Si Somdet of Roi Et Province; and Mueang Maha Sarakham of Maha Sarakham province.
The district is divided into 15 sub-districts (tambons), which are further subdivided into 195 villages (mubans). Roi Et is a town (thesaban mueang) which covers the whole of tambon Nai Mueang. There are a further 14 tambon administrative organizations (TAO).
<small>Missing numbers are tambons which now form the Changhan and Si Somdet Districts.</small>