古特提斯洋（Paleo-Tethys Ocean）是个史前海洋，存在于古生代到三叠纪，位于匈奴地体与冈瓦那大陆之间，位置相当于现今的印度洋与南亚地区。

在奥陶纪晚期，匈奴地体分裂成为欧匈地体及亚匈地体，并自冈瓦那大陆分离，古特提斯洋开始形成。阿瓦隆尼亚大陆也自冈瓦那大陆分离，形成瑞亚克洋。

在志留纪晚期，华北陆块、华南陆块自冈瓦纳大陆分离，使得原特提斯洋开始缩小，古特提斯洋更为扩张。

泥盆纪，匈奴地体南方出现隐没带，古特提斯洋的海洋地壳开始隐没。冈瓦那大陆往北移动。

在石炭纪晚期，华北陆块与西伯利亚-哈萨克斯坦大陆碰撞，原特提斯洋闭合、消失。欧美大陆与欧匈地体开始碰撞，产生阿利根尼造山运动与华力西造山运动，瑞亚克洋逐渐消失，古特提斯洋西半部开始闭合。

The Paleo-Tethys or Palaeo-Tethys Ocean was an ocean located along the northern margin of the paleocontinent Gondwana that started to open during the Middle Cambrian, grew throughout the Paleozoic, and finally closed during the Late Triassic; existing for about 400 million years.