Mueang Chai Nat (Thai: เมืองชัยนาท, pronounced [mɯ̄a̯ŋ t͡ɕʰāj nâːt]) is the capital district (amphoe mueang) of Chai Nat province, central Thailand.

Neighbouring districts are (from the east clockwise) Sapphaya, Sankhaburi, Hankha, Wat Sing, and Manorom of Chai Nat province; and Takhli of Nakhon Sawan province.

On 29 April 1917 the district's name was changed from Mueang to Ban Kluai (บ้านกล้วย).

[2] The district is divided into nine sub-districts (tambons), which are further subdivided into 81 villages (mubans).

Chai Nat is a town (thesaban mueang) which covers tambon Nai Mueang and parts of Ban Kluai, Tha Chai, and Khao Tha Phra.