Phibun Mangsahan (Thai: พิบูลมังสาหาร, pronounced [pʰí.būːn māŋ.sǎː.hǎːn]) is a district (amphoe) in the central part of Ubon Ratchathani province, northeastern Thailand.

Neighboring districts are (from the south clockwise) Buntharik, Det Udom, Na Yia, Sawang Wirawong, Tan Sum, Si Mueang Mai, Khong Chiam and Sirindhorn of Ubon Ratchathani Province.

[1] Phibun Mangsahan is divided into 14 sub-districts (tambons), which are further subdivided into 180 administrative villages (mubans).

Missing numbers belong to tambon which now form Sirindhorn District.

This Ubon Ratchathani Province location article is a stub.