Thomson's gazelle males defend small territories and attempt to mate with females in that area. Females prefer rich foraging grounds, so preferred territories are those in areas with good grazing. Males use markings from preorbital glands and dung to advertise their territories and actively defend them against other males. They sometimes attempt to "herd" females in order to keep them in their territory for longer.

Mating System: polygynous

There is little available information on breeding in Thomson's gazelles. Thomson's gazelles mate twice yearly. Gestation is for 6 months and the majority of births occur right after the rainy season, with a single calf being born at 2 to 3 kg.

Breeding interval: Thomson's gazelles can breed twice a year.

Breeding season: Most breeding is timed so that most births occur right after the rainy season, although births can occur throughout the year.

Range number of offspring: 1 (low) .

Average number of offspring: 1.

Average gestation period: 6 months.

Range birth mass: 2 to 3 kg.

Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); viviparous

Thomson's gazelle calves are precocial at birth, able to stand and walk soon after, although they spend their first days hidden and motionless in the grass. The mother will leave the young in high grass and frequently come back a few times during the day to nurse. After this hiding period, the young follow and accompany their mother with the herd.

Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female)