What album has sold the most copies in music history?

The top two keep flip-flopping, but currently, the biggest selling album of all time is The Eagles, "Their Greatest Hits 1971–1975", followed, of course, by Michael Jackson's "Thriller."

Eagles: Their Greatest Hits
Asylum | 1976

This is the only one I found in USA. Or did you mean the world?

with the Eagles Greatest Hits.

Honorable mention: samantha, one minute behind, was obviously working on posting the correct answer at the same time.

'fuse, this question has been a staple at Trivia Nights for the past 4 years or so, with the answers see-sawing between tha two you mention. I had always assumed that the inconsistencies of answers was due to soem sort of difference in counting sales or that one was the world best-seller and the other the US best-seller. Even the sources I and others checked gave conflicting answers. Has the lead really changed that often? Is that why the answers have bounced back and forth ?

They generally stay within a million or so from one another. To fix a point in time, "The Eagles: Their Greatest Hits 1971 - 1975" was the largest selling album of the 20th Century (about 26 million at that time) and "Thriller," at about 25 million at that time, was the largest selling album by a male artist. I wish I had a "record" of the race between the two, but don't.

My further understanding is that this may be "certified" sales in the U. S. alone. Worldwide sales may put "Thriller" back on top, but I don't have a definitive source for this. Others will better information are welcomed and encouraged to provide input!