The lyre (Greek: λύρα, lýra) is a string instrument known for its use in Greek classical antiquity and later periods. The lyre is similar in appearance to a small harp but with distinct differences. The word comes via Latin from the Greek;^[1] the earliest reference to the word is the Mycenaean Greek ru-ra-ta-e, meaning "lyrists" and written in the Linear B script.^[2] The lyres of Ur, excavated in ancient Mesopotamia (modern Iraq), date to 2500 BC.^[3] The earliest picture of a lyre with seven strings appears in the famous sarcophagus of Hagia Triada (a Minoan settlement in Crete). The sarcophagus was used during the Mycenaean occupation of Crete (1400 BC).^[4][5] The recitations of the Ancient Greeks were accompanied by lyre playing.

The lyre of classical antiquity was ordinarily played by being strummed with a plectrum(pick), like a guitar or a zither, rather than being plucked with the fingers as with a harp. The fingers of the free hand silenced the unwanted strings in the chord. However, later lyres were played with a bow, including in Europe and parts of the Middle East.

"Lyre" can either refer specifically to an amateur instrument, which is a smaller version of the professional cithara and eastern-Aegean barbiton, or "lyre" can refer generally to all three instruments as a family.

In organology, lyres are defined as "yoke lutes", being lutes in which the strings are attached to a yoke which lies in the same plane as the sound-table and consists of two arms and a cross-bar.

The term is also used metaphorically to refer to the work or skill of a poet, as in Shelley's"Make me thy lyre, even as the forest is"^[6] or Byron's "I wish to tune my quivering lyre,/To deeds of fame, and notes of fire"^[7]

A classical lyre has a hollow body or sound-chest (also known as soundbox or resonator), which, in ancient Greek tradition, was made out of turtle shell.^[8] Extending from this sound-chest are two raised arms, which are sometimes hollow, and are curved both outward and forward. They are connected near the top by a crossbar or yoke. An additional crossbar, fixed to the sound-chest, makes the bridge which transmits the vibrations of the strings. The deepest note was that farthest from the player's body; as the strings did not differ much in length, more weight may have been gained for the deeper notes by thicker strings, as in the violin and similar modern instruments, or they were tuned by having a slacker tension. The strings were of gut. They were stretched between the yoke and bridge, or to a tailpiece below the bridge. There were two ways of tuning: one was to fasten the strings to pegs which might be turned; the other was to change the place of the string upon the crossbar; probably both expedients were used simultaneously.

According to ancient Greek mythology, the young god Hermes stole a herd of sacred cows from Apollo. In order not to be followed, he made shoes for the cows which forced them to walk backwards. Apollo, following the trails, could not follow where the cows were going. Along the way, Hermes slaughtered one of the cows and offered all but the entrails to the gods. From the entrails and a tortoise/turtle shell, he created the Lyre. Apollo, figuring out it was Hermes who had his cows, confronted the young god. Apollo was furious, but after hearing the sound of the lyre, his anger faded. Apollo offered to trade the herd of cattle for the lyre. Hence, the creation of the lyre is attributed to Hermes. 

Locales in southern Europe, western Asia, or north Africa have been proposed as the historic birthplace of the genus. The instrument is still played in north-eastern parts ofAfrica.

Some of the cultures using and developing the lyre were the Aeolian and Ionian Greek colonies on the coasts of Asia (ancient Asia Minor, modern day Turkey) bordering the Lydian empire. Some mythic masters like Musaeus, and Thamyris were believed to have been born in Thrace, another place of extensive Greek colonization. The name kissar (cithara) given by the ancient Greeks to Egyptian box instruments reveals the apparent similarities recognized by Greeks themselves. The cultural peak of ancient Egypt, and thus the possible age of the earliest instruments of this type, predates the 5th century classic Greece. This indicates the possibility that the lyre might have existed in one of Greece's neighboring countries, either Thrace, Lydia, or Egypt, and was introduced into Greece at pre-classic times.

The number of strings on the classical lyre varied at different epochs, and possibly in different localities—four, seven and ten having been favorite numbers. They were used without a fingerboard, no Greek description or representation having ever been met with that can be construed as referring to one. Nor was a bow possible, the flat sound-board being an insuperable impediment. The pick, or plectrum, however, was in constant use. It was held in the right hand to set the upper strings in vibration; when not in use, it hung from the instrument by a ribbon. The fingers of the left hand touched the lower strings (presumably to silence those whose notes were not wanted).

There is no evidence as to the stringing of the Greek lyre in the heroic age. Plutarch says that Olympus and Terpander used but three strings to accompany their recitation. As the four strings led to seven and eight by doubling the tetrachord, or series of four tones filling in the interval of a perfect fourth, so the trichord is connected with the hexachord or six-stringed lyre depicted on many archaic Greek vases. The accuracy of this representation cannot be insisted upon, the vase painters being little mindful of the complete expression of details; yet one may suppose their tendency would be rather to imitate than to invent a number. It was their constant practice to represent the strings as being damped by the fingers of the left hand of the player, after having been struck by the plectrum which he held in the right hand. Before Greek civilization had assumed its historic form, there was likely to have been great freedom and independence of different localities in the matter of lyre stringing, which is corroborated by the antique use of the chromatic (half-tone) and enharmonic (quarter-tone) tunings pointing to an early exuberance, and perhaps also to a bias towards refinements of intonation.