膜果泽泻（学名：Alisma lanceolatum）为泽泻科泽泻属的植物。分布在大洋洲、非洲、中亚、欧洲以及中国的**等地，一般生长在静水中和沼泽地，目前尚未由人工引种栽培。

Alisma lanceolatum is a species of aquatic plant in the water plantain family known by the common names lanceleaf water plantain and narrow-leaved water plantain. It is widespread across Europe, North Africa and temperate Asia. It is naturalized in Australia, New Zealand, Oregon, California and British Columbia. It is considered a noxious weed in some places.