Sanam Chai Khet (, ) is a district (amphoe) in the eastern part of Chachoengsao province, central Thailand.
Mueang Sanam Chai Khet was a city of the Ayutthaya Kingdom, a contemporary of neighboring Mueang Phanat Nikhom and Phanom Sarakham.
Being part of Phanom Sarakham district, on 6 January 1966 the three tambons, Khu Yai Mi, Tha Kradan, and Tha Takiap, were split off to form the minor district (king amphoe) Sanam Chai (à ¸ªà ¸Âà ¸²à ¸¡à ¹Âà ¸Âà ¸¢). It was renamed Sanam Chai Ket on 14 December 1972, and upgraded to a full district on 28 June 1973.
Neighboring districts are (from the west clockwise): Plaeng Yao and Phanom Sarakham of Chachoengsao Province; Si Maha Phot and Kabin Buri of Prachinburi province; Khao Chakan of Sa Kaeo province; Tha Takiap of Chachoengsao Province; and Ko Chan of Chonburi province.
Sanam Chai Khet is divided into four sub-districts (tambons), which are further subdivided into 70 administrative villages (mubans).
<small>Missing numbers are tambon which now form Tha Takiap.</small>
There is one sub-district municipality (thesaban tambon) in the district, Sanam Chai Khet (Thai: ) consisting of parts of sub-district Khu Yai Mi.
There are four sub-district administrative organizations (SAO) in the district: