Chong Mek (Thai: ช่องเม็ก) is a border town in the Isan region of Thailand.

It is located in the Sirindhorn District of Ubon Ratchathani Province, about 90 kilometres (60 mi) east of Ubon Ratchathani.

[1] Vang Tao is the settlement on the Lao side.

The town has a busy market popular with Thai visitors, however its popularity has diminished since the opening of the bridge at Mukdahan in 2007.

[2] About 5 km (3 mi) west of Chong Mek is the large Sirindhorn Reservoir created by the construction of the Sirindhorn Dam in 1971.