richomonas (T.) vaginalis a protozoan parasite that causes trichomoniasis is one of the most widespread sexually transmitted diseases. Aim of the present study is to evaluate the in vitro antitrichomonal properties of plant extracts of Quercus (Q.) infectoria, Pistacia (P.) khinjuk, and Satureja (S.) khouzestanica that are ethno-medicinally used in Iran against T. vaginalis trophozoites. In this study, the in vitro anti-T. vaginalis activities of the Q. infectoria, P. khinjuk, and S. khouzestanica extracts against T. vaginalis clinical isolates were assessed by Trypan Blue exclusion assay. The effect of the extracts on induced apoptosis in T. vaginalis trophozoites was evaluated using the fluorescein isothiocyanate (FITC) Annexin V staining kit. The Q. infectoria methanolic extract was significantly (P<0.001) more effective than the other tested extracts. It demonstrated lower IC50 values for trophozoite of T. vaginalis. Q. infectoria methanolic extract exhibited significantly (P<0.001) a higher rate of apoptosis on T. vaginalis trophozoite than other tested extracts and control group. Results of the study revealed that Q. infectoria extract can be considered as a suitable choice for medical studies to treat trichomoniasis. However, additional clinical studies are necessary to evaluate accurate biological effects of this plant on volunteer human subjects.