乳母，又称乳娘、奶娘、奶妈、奶母、奶婆，是雇用来以母乳喂哺婴儿的妇女。在古代，奶粉或其他母乳代用品未发明或未普及时，婴儿的生母如不能或不愿意哺育其子女，往往会雇用乳母。尤其是上层社会、宫廷，不少女性都不会亲自喂哺子女，因此雇用乳母在上层社会十分普遍。

雇用乳母的原因有：

此外，多胞胎的母亲即使有喂哺母乳，亦会因为奶水不足以喂哺所有婴儿而雇用乳母。

有些乳母在小孩出生时也兼任稳婆。

A wet nurse is a woman who breast feeds and cares for another's child. Wet nurses are employed when the mother is unable or chooses not to nurse the child herself. Wet-nursed children may be known as "milk-siblings", and in some cultures the families are linked by a special relationship of milk kinship. Mothers who nurse each other's babies are engaging in a reciprocal act known as cross-nursing or co-nursing.