Chiang Khong (Thai: เชียงของ, pronounced [t͡ɕʰīa̯ŋ kʰɔ̌ːŋ]; Lanna script: ) is a district (amphoe) located in the northeastern part of Chiang Rai province, northern Thailand, with its seat being Wiang. The district borders six other districts in Chiang Rai province, with its north and northeast being bounded by the Mekong River, being connected to Laos on the other side by the Fourth Thai–Lao Friendship Bridge.

After the defeat of Shan rebels in the Ngiao rebellion and the loss of their base of operations in Phrae in 1902, some Shans decided to regroup around Chiang Saen - in Chiang Saen district - and Chiang Khong on the Lao side when it was a demilitarized territory part of Siam. After countless raids in Chiang Khong, the local chief stepped down in early 1904 and was replaced by a Shan. However, Chiang Khong descended into anarchy by May under the rule of the Shans. When the rest of Laos was handed over to the French, the Siamese got permission to enter the previous demilitarized zone and defeat the Shans, where they easily captured back Chiang Khong with no resistance.^[1]

The Phi Pan Nam mountains and their wide intermontane basins dominate the landscape of the district. The 1,328 m high Doi Luang Pae Mueang massif (ดอยหลวงแปเมือง) rises west of Chiang Khong town. The Mekong River flows at the northern end of the district, partially forming the boundary with Laos. Another important river is the Ing, a tributary of the Mekong.

Neighboring districts are (from the southeast clockwise): Wiang Kaen, Khun Tan, Phaya Meng Rai, Wiang Chiang Rung, Doi Luang and Chiang Saen of Chiang Rai Province. To the east is Bokeo province of Laos.