本条目不是忒堤斯或泰美斯.

忒提斯（希腊语：Θέτις）为古希腊神话中的海洋女神，是珀琉斯的妻子，阿基里斯的母亲。忒提斯是一名宁芙仙女但却嫁给一个凡人（珀琉斯），而生下了特洛伊战争的英雄阿基里斯。

忒提斯做为一名女神是不死的，但他的儿子阿基里斯是半神血统，本来难免一死，可是忒提斯希望自己的孩子跟她一样长生不老所以试着将孩子放到天火中烤以提炼他身体内的神力（另有一说是将阿基里斯倒浸在冥河之中）。正在她握着他的脚踝将他炼在天火中的时候，她突然被丈夫发现而匆忙把孩子从火中拿出来，结果阿基里斯真的全身炼到了刀枪不入，惟有脚踝，即忒提斯手握着的地方是例外，以后他脚踝也正成为他的致命弱点。

Thetis (/ˈθɛtɪs/; Greek: Θέτις [tʰétis]), is encountered in Greek mythology mostly as a sea nymph or known as the goddess of water, one of the 50 Nereids, daughters of the ancient sea god Nereus.

When described as a Nereid in Classical myths, Thetis was the daughter of Nereus and Doris, and a granddaughter of Tethys with whom she sometimes shares characteristics. Often she seems to lead the Nereids as they attend to her tasks. Sometimes she also is identified with Metis.