The Elgin Marbles () are a collection of Ancient Greek sculptures from the Parthenon and other structures from the Acropolis of Athens, removed from Ottoman Greece to Britain by agents of Thomas Bruce, 7th Earl of Elgin, and now held in the British Museum. The majority of the sculptures were created in the 5th century BCE under the direction of sculptor and architect Phidias.

The term Parthenon Marbles or Parthenon Sculptures (Greek: Γλυπτά του Παρθενώνα) refers to sculptures—the frieze, metopes and pediments—from the Parthenon held in various collections, principally the British Museum and Acropolis Museum.

From 1801 to 1812, Elgin's agents removed about half the surviving Parthenon sculptures, as well as sculptures from the Erechtheion, the Temple of Athena Nike and the Propylaia, sending them to Britain in efforts to establish a private museum. Elgin stated he removed the marbles with permission of the Ottoman officials who exercised authority in Athens at the time. However, the veracity of this claim has been disputed.

The marbles' presence in the British Museum is the subject of longstanding international controversy. In Britain, the acquisition of the collection was supported by some, while others, such as Lord Byron, likened Elgin's actions to vandalism or looting. A UK parliamentary inquiry in 1816 concluded that Elgin had acquired the marbles legally. Elgin sold them to the British government in that year, after which they passed into the trusteeship of the British Museum.

In 1983 the Greek government formally asked the UK government to return the marbles to Greece, and subsequently listed the dispute with UNESCO. The UK government and British Museum declined UNESCO's offer of mediation. In 2021, UNESCO called upon the UK government to resolve the issue at the intergovernmental level.

The Greek government and supporters of the marbles' return to Greece have argued that the marbles were obtained illegally or unethically, that they are of exceptional cultural importance to Greece, and that their cultural value would be best appreciated in a unified public display with the other major Parthenon marbles and Greek antiquities in the Acropolis Museum. The UK government and British Museum have argued that the marbles were obtained legally, that their return would set a precedent which could undermine the collections of the major museums of world culture, and that the British Museum's collection allows the marbles to be better viewed in the context of other major ancient cultures and thus complements the perspective provided by the Acropolis Museum. Discussions between UK and Greek officials about the future of the marbles are ongoing.