Selfridges Retail Limited (doing business as Selfridges and occasionally Selfridges & Co.) is a British department store chain. It was founded by Harry Gordon Selfridge in 1909. The historic Daniel Burnham-designed Selfridges flagship store at 400 Oxford Street in London opened on 15 March 1909 and is the second-largest shop in the UK (after Harrods). Other Selfridges stores opened in the Manchester area at the Trafford Centre (1998) and at Exchange Square (2002), and in Birmingham at the Bullring (2003).

During the 1940s, smaller provincial Selfridges stores were sold to the John Lewis Partnership, and in 1951, the original Oxford Street store was acquired by the Liverpool-based Lewis's chain of department stores. Lewis's and Selfridges were then taken over in 1965 by the Sears Group, owned by Charles Clore. Expanded under the Sears Group to include branches in Manchester and Birmingham, the chain was acquired in 2003 by Canada's Galen Weston for £598 million. In December 2021, the Weston family agreed to sell the majority of Selfridges Group for around £4 billion to a joint venture between Thai conglomerate Central Group and Austria's Signa Holding. The acquisition was completed on 23 August 2022. However, after Signa faced financial difficulties and declared bankruptcy, Saudi Arabia's Public Investment Fund (PIF) acquired Signa's shares in Selfridges, becoming a co-owner alongside the Central Group.

The basis of Harry Gordon Selfridge's success was his relentlessly innovative marketing, which was elaborately expressed in his Oxford Street store. Originally from America himself, Selfridge attempted to dismantle the idea that consumerism was strictly an American phenomenon. He tried to make shopping a fun adventure and a form of leisure instead of a chore, transforming the department store into a social and cultural landmark that provided women with a public space in which they could be comfortable and legitimately indulge themselves. Emphasizing the importance of creating a welcoming environment, he placed merchandise on display so customers could examine it, and moved the highly profitable perfume counter front-and-centre on the ground floor.

Either Selfridge or Marshall Field is popularly held to have coined the phrase "the customer is always right".

In 1909, after the first cross-Channel flight, Louis Blériot's monoplane, the Blériot XI, was put on display at Selfridges, where it was seen by 150,000 people over a four day period. John Logie Baird made the first public demonstration of moving silhouette images by television from the first floor of Selfridges from 1 to 27 April 1925.

In the 1920s and 1930s, the roof of the store hosted terraced gardens, cafes, a mini golf course and an all-girl gun club. The roof, with its extensive views across London, was a common place for strolling after a shopping trip and was often used for fashion shows.

During the Second World War, the store's basement was used as an air-raid shelter and during raids employees were usually on the lookout for incendiary bombs and took watch in turns.

A Milne-Shaw seismograph was set up on the Oxford Street store's third floor in 1932, attached to one of the building's main stanchions, where it remained unaffected by traffic or shoppers. It successfully recorded the Belgian earthquake of 11 June 1938, which was also felt in London. In 1947, it was given to the Science Museum.