Koster is a small farming town situated on the watershed between the Orange and Limpopo Rivers in North West Province of South Africa.

The town was proclaimed in 1913 and named after Bastiaan Koster, the original farm owner.

It was founded on the farm Kleinfontein in 1913, and has been administered by a village council since January 1931.

Said to have been named either after Dr Herman Jacob Coster (1866–1899), State Attorney of the South African Republic, after its surveyor, or after Bastiaan Hendricus Koster, owner of the farm Kleinfontein.

This North West Province location article is a stub.