Si Chiang Mai (Thai: ศรีเชียงใหม่, pronounced [sǐː t͡ɕʰīa̯ŋ màj]) is a district (amphoe) in the western part of Nong Khai province, northeastern Thailand.

Si Chiang Mai district was established by King Setthathirath of Lan Xang Kingdom.

[1] Neighboring districts are (from the southeast clockwise): Tha Bo, Pho Tak, and Sangkhom of Nong Khai Province.

Si Chiang Mai is divided into four sub-districts (tambons), which are further subdivided into 43 administrative villages (mubans).

The missing number is a tambon which now forms Pho Tak District.