The gemsbok or gemsbuck (Oryx gazella) is a large antelope in the Oryx genus. It is native to the arid regions (for example the Kalahari Desert) of southern Africa, but formerly some authorities included the East African Oryx as a subspecies. Its current population in South Africa is 373,000.

The name "gemsbok" in English is derived from Afrikaans gemsbok, itself derived from the Dutch name of the male chamois, gemsbok. Although there are some superficial similarities in appearance (especially in the facial pattern), the chamois and the oryx are not closely related. The usual pronunciation in English is /ˈɡɛmzbɒk/.

Gemsbok are light brownish-grey to tan in colour, with lighter patches to the bottom rear of the rump. Their tails are long and black in colour. A blackish stripe extends from the chin down the bottom edge of the neck through the join of the shoulder and leg along the lower flank of each side to the blackish section of the rear leg. They have muscular necks and shoulders and their legs have white 'socks' with a black patch on the front of both the front legs and both genders have long straight horns. Comparably, the East African Oryx lacks a dark patch at the base of the tail, has less blackish on the legs (none on the hindlegs), and less blackish on the lower flanks.