The rock band have reached the milestone with their Greatest Hits album, which was released in 1981 and has continued to rack up strong sales.
The Official Charts Company, which has announced the milestone, said that as well as sales on physical formats, the album has also been downloaded 124,000 times in the UK.
It has been estimated that one in four British homes has a copy of the album, which includes hits such as Bohemian Rhapsody and Another One Bites The Dust.
Guitarist Brian May said the figure was "incredible". In a video message for OfficialCharts.com, he said: "I just want to say thanks to everyone who has supported us through the years, we hope to continue to serve you."
Martin Talbot, chief executive of the Official Charts Company, said: "Ever since it was first released in 1981, this package of classic pop and rock tracks has been an indispensable item in every music fan's record collection - perhaps the definitive greatest hits album."
Gennaro Castaldo, of music industry body the BPI, said: "Queen are a part of our music heritage now, with a timeless appeal that will ensure demand for their songs will continue as new generations of fans keep coming through."
Their Greatest Hits II album released in October 1991, a month before the death of singer Freddie Mercury - is the tenth biggest seller of all time in the UK with 3.9 million sales.
:: All-time top five best-selling albums in the UK:
1. Greatest Hits - Queen (6m)
2. Gold - Abba (5.1m)
3. Sgt Pepper's Lonely Hearts Club Band - The Beatles (5.1m)
4. 21 - Adele (4.7m)
5. (What's The Story) Morning Glory? - Oasis (4.6m)