In the present investigation, the seroprevalence of Toxoplasma gondii antibodies in 455 Tibetan sheep in Tibet, China, was examined using an indirect hemagglutination test. Of these, 26 (5.7%) Tibetan sheep were seropositive at the cut-off of 1:64 serum dilution. The seroprevalence ranged from 2.2% to 8.9% among Tibetan sheep of <1-yr-old, 1–3-yr-old, and >3-yr-old, but the differences among the age groups were not significant (P > 0.05). The prevalence in male Tibetan sheep (2.8%) was lower than that in female Tibetan sheep (6.6%), but the difference was not statistically significant (P > 0.05). The results of this survey indicated the presence of T. gondii infection in Tibetan sheep, which may cause economic losses to the local livestock industry and which poses a potential threat to human health in this area.