Top Pop Catalog Albums is a fifty-position weekly albums chart produced by Billboard magazine which ranks the best selling catalog titles, regardless of genre. Billboard defines a catalog title as one that is more than eighteen months old and that has fallen below position 100 on the Billboard 200. Albums meeting these criteria are removed from the Billboard 200 and begin a new chart run on Top Pop Catalog Albums.
Top Pop Catalog Albums also contains reissues of older albums. An album need not have spent any weeks on the Billboard 200 to be eligible for Top Pop Catalog Albums (this occasionally occurs if an act has a breakthrough release which prompts a significant increase in sales of prior albums that were not big sellers upon their initial release).

The only exception to the "eighteen months old" rule pertains to holiday releases (for example, Christmas albums). A "holiday" release is eligible for the Billboard 200 only during its initial year of release. After its first year, a holiday-related album appears on Top Pop Catalog Albums. Many consistent-sellers make return trips to Top Pop Catalog Albums each November through January (it is not rare to see the top 20 or 30 positions occupied by holiday albums during December).

A unique feature of the Top Pop Catalog Albums chart is the replacement of the "weeks on chart" column (a standard in Billboard's other charts) with a "total weeks" column, which is a cumulative total of weeks an album spent on both the Billboard 200 and the Top Pop Catalog Albums chart. The "total weeks" longevity record (by a large margin) is held by Pink Floyd's The Dark Side of the Moon, which has a cumulative total of over 1,600 chart weeks (more than 31 years).

The issue dated July 11, 2009 was the first time any catalog album outsold the number-one album on the Billboard 200. Three of Michael Jackson's albums (Number Ones, The Essential Michael Jackson and Thriller) claimed positions 1-3 respectively on Top Pop Catalog Albums and Top Comprehensive Albums in the week following Jackson's death. Additionally, the entire top nine positions on Top Pop Catalog Albums were owned by Jackson, including a hits set by The Jackson 5.