Nakhon Ratchasima (Thai: นครราชสีมา), often called Korat (RTGS Khorat, โคราช), is one of the northeast provinces (changwat) of Thailand. Neighbouring provinces are (clockwise, from north) Chaiyaphum, Khon Kaen, Buriram, Sa Kaeo, Prachinburi, Nakhon Nayok, Saraburi, and Lopburi.
The capital of the province is the city of Nakhon Ratchasima in Mueang Nakhon Ratchasima District, also called Korat or Khorat. The Khmer name for the province is Nokor Reach Seima. The Malay name is Negara Raja Sima.