Maha Rat (Thai: มหาราช, pronounced [māhǎː râːt]) is a district (amphoe) in the northern part of Ayutthaya province in Thailand.

Originally the district was named Khwaeng Nakhon Yai.

It was converted to an amphoe in 1914 and changed its name to Maha Rat in 1917.

The district is divided into 12 sub-districts tambon, which are further subdivided into 58 villages muban.

Rong Chang covers the whole tambon Nam Tao, Rong Chang, Chao Pluk, and Phit Phian.