The France international will wear the No.18 shirt and Loftus Road and is eligible to make his Hoops debut against West Ham on Saturday, subject to receiving international clearance.
Harry Redknapp told the club's official website: "I'm delighted to bring him in – he's a great buy for us.
"He's always been a player I've admired. I've watched him on so many occasions throughout the last few years. I actually spent three or four hours with him last year so he knew what I thought of him and I think that was important.
"He's quick, can score goals and makes great runs. His movement is excellent. He's got the potential to be a really outstanding striker."
Remy had looked set to join Newcastle but has opted for west London instead, with the former Nice man hailing Redknapp as being key to his decision.
The striker added: "Harry played a big part in me coming here. I spoke to him and [owner] Tony Fernandes at length and they made it clear they wanted me here. They gave me the right motivation to join QPR.
"I want to develop my game here. This season the objective is to stay up but beyond that we have greater objectives.
"After seven years in France, this is the right time for me to pursue a new challenge in the Premier League – the best League in the world.
"I am confident I can adapt to the Premier League. My main characteristics have taken me to the level I am at today but I am keen to keep improving in the Premier League."