If I Could Turn Back Time: Cher's Greatest Hits is the fourth U.S. compilation album by American singer-actress Cher, released on March 9, 1999, by Geffen. In January 2000, the album was certified Gold by the RIAA for selling more than 500,000 copies in the US. Billboard stated in November 2011 that the album had sold 955,000 copies in the US.

The Greatest Hits is the second European compilation album by American singer-actress Cher, released on November 30, 1999, by Warner Music U.K.'s WEA label. The album was very successful worldwide, topping the charts in Austria, Germany, and Denmark. It peaked at #7 on the official UK Albums Chart, and reached the top 10 in several countries across Europe and the rest of the world. This compilation was not available in the United States, due to the release of the US-only compilation, If I Could Turn Back Time: Cher's Greatest Hits which was released that same year. The album sold 3 million copies as of January 2000.