石棺（Sarcophagus），是一种石制的棺材或尸体容器。

公元前5世纪，希腊历史学家希罗多德指出，早期石棺由一种特殊的岩石造成，它们能侵蚀棺内尸体的肉。尤其是采用自特洛亚特阿苏斯的石灰岩“lapis assius”造的棺木，他们能够侵蚀放在里面的尸体，因此也被称为“sarkophagos lithos”（食肉石）。所有用石灰岩做的棺木都有这个特性，但是侵蚀的程度则有不同。

石棺通常会有华丽的纹饰，制作工艺精湛。有些更会独立地建在地面上，作为墓碑的一部分。有些会被埋葬，或放置在地下墓室。在古埃及，石棺通常被用作皇家木乃伊的外部保护层，此外，还有数层的棺木会保着木乃伊。

A sarcophagus (plural, sarcophagi; sarcophaguses) is a box-like funeral receptacle for a corpse, most commonly carved in stone, and displayed above ground, though it may also be buried. The word "sarcophagus" comes from the Greek σάρξ sarx meaning "flesh", and φαγεῖν phagein meaning "to eat", hence sarcophagus means "flesh-eating"; from the phrase lithos sarkophagos (λίθος σαρκοφάγος). Since lithos is Greek for "stone", lithos sarcophagos means "flesh-eating stone". The word also came to refer to a particular kind of limestone that was thought to decompose the flesh of corpses interred within it.