Na Yia (, ; , ) is a district (amphoe) in the central part of Ubon Ratchathani province, northeastern Thailand.
Na Yia was separated from Det Udom district to create a minor district (king amphoe) on 31 May 1993.
On 15 May 2007, all 81 minor districts were upgraded to full districts. On 24 August the upgrade became official.
Neighboring districts are (from the north clockwise): Sawang Wirawong, Phibun Mangsahan, Det Udom and Warin Chamrap.
The district is divided into three sub-districts (tambons), which are further subdivided into 34 villages (mubans). Na Yia is a township (thesaban tambon) which covers parts of tambon Na Yia. There are a further three tambon administrative organizations (TAO).