Abydos (Ancient Greek: Ἄβυδος, Latin: Abydus) was an ancient city and bishopric in Mysia. It was located at the Nara Burnu promontory on the Asian coast of the Hellespont (the straits of Dardanelles), opposite the ancient city of Sestos, and near the city of Çanakkale in Turkey. Abydos was founded in c. 670 BC at the most narrow point in the straits, and thus was one of the main crossing points between Europe and Asia, until its replacement by the crossing between Lampsacus and Kallipolis in the 13th century, and the abandonment of Abydos in the early 14th century.

In Greek mythology, Abydos is presented in the myth of Hero and Leander as the home of Leander. The city is also mentioned in Rodanthe and Dosikles, a novel written by Theodore Prodromos, a 12th-century writer, in which Dosikles kidnaps Rodanthe at Abydos.

In 1675, the site of Abydos was first identified, and was subsequently visited by numerous classicists and travellers, such as Robert Wood, Richard Chandler, and Lord Byron. The city's acropolis is known in Turkish as Mal Tepe.

Following the city's abandonment, the ruins of Abydos were scavenged for building materials from the 14th to the 19th century, and remains of walls and buildings continued to be reported until at least the 19th century, however, little remains and the area was declared a restricted military zone in the early 20th century, thus little to no excavation has taken place.

Abydos is mentioned in the Iliad as a Trojan ally, and, according to Strabo, was occupied by Bebryces and later Thracians after the Trojan War. It has been suggested that the city was originally a Phoenician colony as there was a temple of Aphrodite Porne (Aphrodite the Harlot) within Abydos. Abydos was settled by Milesian colonists contemporaneously with the foundation of the cities of Priapos and Prokonnesos in c. 670 BC. Strabo related that Gyges, King of Lydia, granted his consent to the Milesians to settle Abydos; it is argued that this was carried out by Milesian mercenaries to act as a garrison to prevent Thracian raids into Asia Minor. The city became a thriving centre for tuna exportation as a result of the high yield of tuna in the Hellespont.

Abydos was ruled by Daphnis, a pro-Persian tyrant, in the 520s BC, but was occupied by the Persian Empire in 514. Darius I destroyed the city following his Scythian campaign in 512. Abydos participated in the Ionian Revolt in the early 5th century BC, however, the city returned briefly to Persian control as, in 480, at the onset of the Second Persian invasion of Greece, Xerxes I and the Persian army passed through Abydos on their march to Greece crossing the Hellespont on Xerxes' Pontoon Bridges. After the failed Persian invasion, Abydos became a member of the Athenian-led Delian League, and was part of the Hellespontine district. Ostensibly an ally, Abydos was hostile to Athens throughout this time, and contributed a phoros of 4-6 talents. Xenophon documented that Abydos possessed gold mines at Astyra or Kremaste at the time of his writing.

During the Second Peloponnesian War, a Spartan expedition led by Dercylidas arrived at Abydos in early May 411 BC and successfully convinced the city to defect from the Delian League and fight against Athens, at which time he was made harmost (commander/governor) of Abydos. A Spartan fleet was defeated by Athens at Abydos in the autumn of 411 BC. Abydos was attacked by the Athenians in the winter of 409/408 BC, but was repelled by a Persian force led by Pharnabazus, satrap (governor) of Hellespontine Phrygia. Dercylidas held the office of harmost of Abydos until at least c. 407. According to Aristotle, Abydos had an oligarchic constitution at this time. At the beginning of the Corinthian War in 394 BC, Agesilaus II, King of Sparta, passed through Abydos into Thrace. Abydos remained an ally of Sparta throughout the war and Dercylidas served as harmost of the city from 394 until he was replaced by Anaxibius in c. 390; the latter was killed in an ambush near Abydos by the Athenian general Iphicrates in c. 389/388. At the conclusion of the Corinthian War, under the terms of the Peace of Antalcidas in 387 BC, Abydos was annexed to the Persian Empire. Within the Persian Empire, Abydos was administered as part of the satrapy of Hellespontine Phrygia, and was ruled by the tyrant Philiscus in 368. In c. 360 BC, the city came under the control of the tyrant Iphiades.

Abydos remained under Persian control until it was seized by a Macedonian army led by Parmenion, a general of Philip II, in the spring of 336 BC. In 335, whilst Parmenion besieged the city of Pitane, Abydos was besieged by a Persian army led by Memnon of Rhodes, forcing Parmenion to abandon his siege of Pitane and march north to relieve Abydos. Alexander ferried across from Sestos to Abydos in 334 and travelled south to the city of Troy, after which he returned to Abydos. The following day, Alexander left Abydos and led his army north to Percote. Alexander later established a royal mint at Abydos, as well as at other cities in Asia Minor.