The club are currently 17th in the Premier League table after a string of poor results.
"The Board's commitment to retaining our Premier League status ultimately led to this decision," read a club statement.
"QPR Assistant Manager Mick Jones and First Team Coach Keith Curle have also left the Club."
The 63-year-old joined the R's in 2010 after a spell with Crystal Palace.
Mark Hughes has been named as the early favourite to succeed Warnock at Loftus Road.
Click here for the full statement released by Rangers.