Don Tan (Thai: ดอนตาล, pronounced [dɔ̄ːn tāːn]) is the southeasternmost district (amphoe) of Mukdahan province, northeastern Thailand.

Originally Don Tan was a tambon of Mukdahan district, Nakhon Phanom province.

[3] Neighboring districts are (from the southeast clockwise) Chanuman of Amnat Charoen province; Loeng Nok Tha of Yasothon province; Nikhom Kham Soi and Mueang Mukdahan of Mukdahan Province.

To the east across the Mekong River is the Laotian province of Savannakhet.

The district is divided into seven sub-districts (tambons), which are further subdivided into 62 villages (mubans).