Oi (Oy, Oey;[4] also known as The, Thang Ong, Sok) is an Austroasiatic dialect cluster of Attapeu Province, southern Laos.

The Jeng (Cheng) speak the same language but are ethnically distinct (Sidwell 2003).

[1] Some locations where Oi is spoken in include (Sidwell 2003:26): The Jeng live mostly along the banks of the Sekaman River, in and around Ban Fandeng (Phandɛŋ).

According to Daniell (2020), there are about 20 Oy villages in Attapeu Province, Laos.

The following villages are ordered roughly from west to east, and are located along or near the Sekong River, in an area of Attapeu Province to the west of Attapeu Town.