Deaccessioning is the technical term referring to the expulsion of objects from museum collections. This would be considered an ordinary aspect of museum administration if museums did not play a crucial role in the conservation of cultural heritage. Both linguistically and factually, deaccessioning represents the undoing of accessioning operations, by which objects newly acquired by museums are inscribed into museum registers. Because the act of accessioning constitutes a conferral of status, an expert acknowledgment that the object is worthy of preservation, deaccessioning comes to represent the revocation of this status; that is, it entails the object’s return to the mundane sphere. Deaccessioning usually occurs with the intent of selling the object. The practice first came into the spotlight on 27 February 1972, when in a New York Times article titled “Very Quiet and Very Dangerous,” the art critic and historian John Canaday denounced the Metropolitan Museum of Art’s rumored sale of many prominent artworks earlier that year, including two Manets, a Cézanne, a Renoir, a Gauguin, and a Picasso, questioning the operation on both ethical and financial grounds. The episode became widely known as the “Hoving affair,” from the name of then-director of the Metropolitan Museum, Thomas Hoving, and left a stigma about the practice of selling artworks from museum collections. Since then, deaccessioning has remained an uncomfortable aspect of museum administration, considered by some a legitimate curatorial tool, by others a necessary evil in times of financial stress, and by still others a mark of museum managers’ betrayal of the public trust. To this day, deaccessioning continues to be discussed primarily in relation to art museums and the sale of artworks; however, the term rightfully applies to non-artistic objects, such as books, archival records, or archaeological items, and it does not strictly refer to objects’ sales but more generally to their disposals. Therefore, it also applies to cases where the objects are expelled from collections because of loss, damage, donation, restitution, or repatriation. Deaccessioning can occur for reasons that appear easily defensible. It may occur, for example, because new legislation forces a change of ownership, or because the museum cannot properly care for the object. Nevertheless, it often occurs for dubious reasons, perhaps because the item is considered redundant, uninteresting, or commercially valuable. This bibliography entry draws on interdisciplinary literature to review common arguments both in favor and against deaccessioning. It begins with legal considerations, because the legal profession was the first to develop scholarly interest in this practice, and was later followed by the fields of economics and management. After introducing selected literature from these fields, this entry introduces key sources on deaccessioning policy, representative case studies, and publications oriented toward students and practitioners.