Acanthamoeba spp. commonly cause Acanthamoeba keratitis which is typically associated with the wear of contact lenses. Therefore, finding an economic, efficient, and safe therapy of natural origin is of outmost importance. This study examined the in vitro lethal potential of ethyl acetate and methanol extracts of Helianthemum lippii (L.) (sun roses) against Acanthamoeba castellanii cysts isolated from patients with amoebic keratitis. Both extracts proved to be potent as regard to their lethal effects on A. castellanii cysts with comparable results to chlorhexidine. The ethyl acetate was more promising with cumulative lethality. It showed a highly significant lethal percentage along the duration of treatment. The analysis of the more potent ethyl acetate extract revealed the presence of 2.96 mg/100 g of total phenolics, 0.289 mg/100 ml of total flavonoids and 37 mg/100 mg of total tannins which highlighted their phytomedicinal role.