Yasothon province (Thai: ยโสธร, pronounced [já.sǒː.tʰɔ̄ːn], one of Thailand's seventy-six provinces (changwat), lies in central northeastern Thailand also called Isan. The province was established by the revolutionary council of Field Marshal Thanom Kittikachorn, after its Announcement No. 70 which came into force on 3 March 1972.

Neighboring provinces are (from north clockwise) Mukdahan, Amnat Charoen, Ubon Ratchathani, Sisaket, and Roi Et.

The northern half of the province consists of plains with low hills; the southern part consists of the river lowlands of the River Chi, with ponds and swamps. Yasothon's total forested area is 358 km² (138 sq mi) or 8.7% of the province.

Yasothon soils (rhodic ferralsols) formed in the Triassic before the uplift of the Khorat Plateau, are relict soils made fertile by field termites through bioturbation.

There is one national park, along with five other national parks, make up region 9 (Ubon Ratchathani) of Thailand's protected areas. (Visitors in fiscal year 2024)

The province was created on 1 March 1972, when it was split off from Ubon Ratchathani.

The seal of the province shows two mythical lions, called singh, facing the chedi Prathat Anon, in the temple Wat Maha That in the city of Yasothon. In the legendary account of the founding of the city, a lion came out of the forest when the site was chosen; hence the city was called Ban Singh Tha (Thai: บ้านสิงห์ท่า), Home (of) Imposing Lion. At the bottom of the seal is a lotus flower (Nymphaea lotus), as the lotus is both the provincial flower of the province and of Ubon Ratchathani province, of which Yasothon was part until 1972. The provincial tree is Anisoptera costata. The provincial aquatic life is the sheatfish Ompok bimaculatus.

The province is divided into nine districts (amphoe). The districts are further subdivided into 78 subdistricts (tambon) and 885 villages (muban).