巢鼠（学名：Micromys minutus）为鼠科巢鼠属的动物。

体小，长5－8厘米，尾长能缠绕；尾端上面裸露；体背棕黄或棕褐色，腹面为白色或略带有沙黄色。

The harvest mouse, Micromys minutus, is a small rodent native to Europe and Asia. It is typically found in fields of cereal crops, such as wheat and oats, in reed beds and in other tall ground vegetation, such as long grass and hedgerows. It has reddish-brown fur with white underparts and a naked, highly prehensile tail, which it uses for climbing. It is the smallest European rodent; an adult may weigh as little as 4 grams (0.14 oz). It eats chiefly seeds and insects, but also nectar and fruit. Breeding nests are spherical constructions carefully woven from grass and attached to stems well above the ground.