It depends on whether you are considering published albums, studio albums, collaborations, and re-releases. And whether you count albums by individual members or parts of the group.
Some Examples
-- The Grateful Dead has issued 319 albums (142 separately released), but their discography as a group is only 22 albums (9 arranged and 13 live). There are various remixes, compilations, box sets, and retrospectives that may have previously unreleased material.
-- The Beatles (including UK-only releases) have as many as 31 albums but more than 57 compilation albums.
-- Rush: 18 studio albums + 6 live + 9 video albums = 33.
-- Queen: 15 + 6 + 11 + 3 = 35.
-- AC/DC : 20 studio albums
-- Rolling Stones: 55 albums
-- Tangerine Dream: over 100 albums excluding remixes
-- The Ventures: over 100 including foreign releases
It also comes down to whether to include individual performers, or singles:
-- Elvis Presley: 55 albums and 21 singles
-- Johnny Cash: 96 albums altogether
-- Dolly Parton: 58 studio albums
Perhaps the greatest number by a single artist is Australia's Slim Dusty (1927-2003) who has more than 109 albums over a period of 47 years, including collaborations and live albums.