QR (also known as Quiet Riot, Quiet Riot IV, or QR IV) is the sixth studio album released on October 21, 1988, by the American heavy metal band Quiet Riot. The album featured a major line-up change. Singer and founding member Kevin DuBrow had been fired before the recording sessions began, and replaced by Rough Cutt vocalist Paul Shortino. The band had fired DuBrow mainly because of comments he was making to the metal press about Quiet Riot's supposed superiority over other bands, which strained friendships that members of Quiet Riot had with those bands. Shortino's hiring was not the only line-up change, as Chuck Wright had quit the band and was replaced by Sean McNabb. This left the album with the distinction of being the only Quiet Riot release without DuBrow on vocals, or any other original members (until 1993's Terrified).

Due to the confusion over the album's proper title, Paul Shortino was asked in 2015 on Twitter what the proper name of the album was, and he replied back that the name is simply "QR".

Reaction to the album at the time was tepid, but did manage to attract a bit more interest than the previous album. However, the only major single spawned from the album, "Stay with Me Tonight" made a small dent in the pop charts and the video received moderate airplay on MTV in late 1988, but nothing comparable to the impact that previous albums had.

The album also featured studio musicians Jimmy Waldo (keyboards) and Jimmy Johnson, who played bass on "Stay with Me Tonight" and "Coppin' a Feel". The album was produced by Spencer Proffer, who had produced every Quiet Riot U.S. released album up to this point.

Paul Shortino and Sean McNabb later played together on Rough Cutt's Sneak Peek EP.

The album was remastered on CD in 2010 by Jon Astley.