There is an increasing interest in exploring plant extracts as potential new treatment options for these ailments. Ziziphus vulgaris L. and Camellia sinensis (L.) Kuntze are medicinal plants widely used in different traditional medical practices, especially in Iranian Traditional Medicine, for addressing a range of health issues. Although their biological properties are well-established, their effectiveness against Giardia duodenalis cysts is still uncertain. This research aimed to assess the impact of Z. vulgaris and C. sinensis extracts on G. duodenalis cysts in vitro and to compare their effectiveness with metronidazole. Cysts were extracted from stool samples and concentrated using a 0.85 M sucrose solution. Extracts of Z. vulgaris and C. sinensis were prepared at concentrations of 25, 50, and 100 mg mL-1. The impacts of these extracts at different concentrations were evaluated at 10, 15, 30, 60, and 180 min, and the results were compared to control groups. The collected data were documented and statistically analyzed. The findings revealed that Z. vulgaris extract at a concentration of 100 mg mL-1and C. sinensis extract at a concentration of 50 mg mL-1 showed similar effectiveness to metronidazole in eliminating Giardia cysts. In addition, the cytotoxic effects of Z. vulgaris and C. sinensis extracts, in comparison to metronidazole, indicated a rise in fatality rates with prolonged exposure times and higher extract concentrations (p < 0.05). Therefore, it can be concluded that extracts of Z. vulgaris and C. sinensis are as effective as metronidazole for killing Giardia cysts in vitro.