The 24-year-old, who moved to Loftus Road from Arsenal in 2011, made 24 appearances in QPR's promotion-winning 2013-14 campaign and has now committed himself to the club until 2016.
The Senegal international is the latest player to agree fresh terms with Harry Redknapp's side, following in the footsteps of Clint Hill and Alejandro Faurlin.
"I am so happy to have my future sorted out," the former Juventus loanee told QPR's official website.
"I wanted to stay at QPR and now this is done I can fully concentrate on the challenge that lies ahead.
"I am fully focused on the start of the Premier League season – I'm really looking forward to it.
"Next season is an extremely important one for me, added to the fact we're back in the Premier League.
"I want to show what I can do in the best league in the world for QPR – that's what it's all about."
QPR, who beat Derby County in the Championship play-off final at Wembley in May, open their top-flight campaign with a home match against Hull City on August 16.