Gourgouthakas (; from "small cutting on rocks, in which rain water is collected and from which animals drink water") is a cave located in the Lefka Ori mountains on the Greek island of Crete. Until resurveying in 2022, it was considered the deepest cave in Greece, with an explored depth of , and was the 43rd deepest in the world in 2010. Following the re-survey conducted by the Gourgouthakas expedition of 2022, the depth has been re-evaluated at . A dive of the terminal siphon in 2025 allowed reaching a depth of for 80 meters in length.
Gourgouthakas was discovered in 1990 by the Speleological Mission of the Catamaran team, based in ÃÂontbeliard, France. The depth of 985 m was reached in 1997. In 1998, the same group reached the small lake (sump) at the bottom, at a depth of . The lake has not yet been explored.
The cave is primarily a deep vertical shaft, filled with intersecting arcades and huge stalagmites and stalactites. Due to its configuration, specialized equipment and expertise is required to explore it.