Thule ( Greek: Θούλη, translit. Thoúlē; Latin: Thūlē) is the most northerly location mentioned in ancient Greek and Roman literature and cartography. Modern interpretations have included Orkney, Shetland, northern Scotland, the island of Saaremaa (Ösel) in Estonia, and the Norwegian island of Smøla.

In classical and medieval literature, ultima Thule (Latin "farthest Thule") acquired a metaphorical meaning of any distant place located beyond the "borders of the known world".

By the Late Middle Ages and early modern period, the Greco-Roman Thule was often identified with the real Iceland or Greenland. Sometimes Ultima Thule was a Latin name for Greenland, when Thule was used for Iceland. By the late 19th century, however, Thule was frequently identified with Norway.

In 1910, the explorer Knud Rasmussen established a missionary and trading post in north-western Greenland, which he named "Thule" (later Qaanaaq).

Thule has given its name to the northernmost United States Space Force base, Thule Air Base in northwest Greenland.