In Greek mythology, Clio (/ˈkli.oʊ/ or, more rarely, /ˈklaɪ.oʊ/; from Greek: Κλειώ, Kleiṓ; "made famous" or "to make famous"), also spelled Kleio, is the muse of history, or in a few mythological accounts, the muse of lyre playing. Like all the muses, she is a daughter of Zeus and the Titaness Mnemosyne. Along with her sisters, she was considered to dwell at either Mount Helicon or Mount Parnassos. Other common locations for the Muses were Pieria in Thessaly, near to Mount Olympus. She had one son, Hyacinth, with one of several kings, in various myths—with Pierus, King of Macedon, or with king Oebalus of Sparta, or with king Amyclas, progenitor of the people of Amyclae, dwellers about Sparta. Some sources say she was also the mother of Hymenaios. Other accounts credit her as the mother of Linus, a poet that was buried at Argos, but Linus has a number of differing parents depending upon the account, including several accounts where he is the son of Clio's sisters Urania or Calliope.
All of the Muses were considered to be the best practitioners of their fields, and any mortal challenging them in their sphere was destined to be defeated. They were often associated with Apollo. The most common number of the Muses is 9, but the number is not always consistent in earlier mythologies. Hesiod is usually considered to have set their number, names, and spheres of interest in his poem Theogony.
Clio, sometimes referred to as "the Proclaimer", is often represented with an open scroll of parchment scroll or a set of tablets. The name is etymologically derived from the Greek root κλέω/κλείω (meaning "to recount," "to make famous," or "to celebrate").
In her capacity as "the proclaimer, glorifier and celebrator of history, great deeds and accomplishments," Clio is the namesake of various modern brands, including the Clio Awards for excellence in advertising. The Cleo of Alpha Chi society at Trinity College is named after the muse. 'Clio' also represents history in some coined words in academic usage: cliometrics, cliodynamics.