Chian Yai (Thai: เชียรใหญ่, pronounced [t͡ɕʰīa̯n jàj]) is a district (amphoe) in the southeastern part of Nakhon Si Thammarat province, southern Thailand.

Neighboring districts are (from the north clockwise): Pak Phanang, Hua Sai, Cha-uat, and Chaloem Phra Kiat.

The district is divided into 10 sub-districts (tambons), which are further subdivided into 98 villages (mubans).

Missing numbers belong to tambons which now form Chaloem Phra Kiat.

This Nakhon Si Thammarat Province location article is a stub.