勒托（希腊语：Λητώ，多利安语：Λατώ）希腊神话中的一个女提坦。她是宙斯的众多配偶之一，并且是阿波罗与阿耳忒弥斯的母亲。在罗马神话中，她的对应者是拉托娜。

根据赫西俄德的记载，勒托是提坦神科俄斯与福柏的女儿，天神乌剌诺斯和地神该亚的孙女；她的出生地据说是科斯岛。勒托与奥林波斯教的主神宙斯结合，生育了两名主要神祇，即阿波罗与阿耳忒弥斯。关于阿波罗与阿耳忒弥斯，品达说这两人是双胞胎，其他资料则认为他们是在不同地点出生的。

勒托在传统上是一个用来衬托阿波罗与阿耳忒弥斯的母神的形象，在神话中涉及她的部分主要是关于生育阿波罗的故事。在阿波罗与阿耳忒弥斯出生后，勒托的形象几乎从希腊神话中消失了，“黑暗掩盖了勒托”，这可能是因为神谱提到勒托出生时穿着黑衣服，所以生出两位明亮的孩子后便退出神话舞台，这是常见的光明与黑暗的反差关系。在神话中，勒托总体上是一个逆来顺受的母亲的形象，但也有例外。

In Greek mythology, Leto (/ˈliːtoʊ/; Greek: Λητώ Lētṓ; Λατώ, Lātṓ in Dorian Greek, etymology and meaning disputed) is a daughter of the Titans Coeus and Phoebe, the sister of Asteria, and the mother, by Zeus, of Apollo and Artemis.

The island of Kos is claimed as her birthplace. In the Olympian scheme, Zeus is the father of her twins, Apollo and Artemis, the Letoides, which Leto conceived after her hidden beauty accidentally caught the eyes of Zeus. Classical Greek myths record little about Leto other than her pregnancy and her search for a place where she could give birth to Apollo and Artemis, since Hera in her jealousy had caused all lands to shun her. Finally, she finds an island that is not attached to the ocean floor so it is not considered land and she can give birth. This is her one active mythic role: once Apollo and Artemis are grown, Leto withdraws, to remain a dim and benevolent matronly figure upon Olympus, her part already played. In Roman mythology, Leto's equivalent is Latona, a Latinization of her name, influenced by Etruscan Letun.