The 24-year-old, who scored for Holland in their 2-0 World Cup group stage victory over Chile, only moved to Norwich last summer but has left the Norfolk club following their relegation from the Barclays Premier League.
Rangers passed the Canaries on their way up through the play-offs and manager Harry Redknapp has swooped to bring in Fer, who continues the summer recruitment in west London following moves for Rio Ferdinand, Steven Caulker and Jordon Mutch - with Mauricio Isla brought in on loan.
"Leroy's arrival is a massive boost for us," Redknapp said
"He's another excellent signing and I'm delighted we've been able to get him to QPR."
Redknapp stressed following Saturday's 1-0 home defeat to Hull that he wanted to bring in new faces and could still add further signings after securing Fer's signature
Fer was given an extended break following Holland's third-place finish in Brazil but he did appear for Norwich as a late substitute in their 3-0 win over Watford.
The former FC Twente midfielder was originally included in Neil Adams' squad to take on Blackburn on Tuesday evening but withdrew to travel to west London for a medical.
The deal was confirmed on Wednesday evening and Fer is raring to go now he has signed for the Hoops.
"I can't wait to get started here," he said.
"It was always my dream to stay in England, in the Premier League
QPR did well last season to come up and the squad is full of top players, so I'm delighted to be here.
"Harry told me I was a big target for him and when you hear that from a coach, you want to work with them and play for them
I'm just looking forward to showing what I'm capable of here at QPR."
Having collected seven international caps to date, Fer will also be hoping a move to stay in England's top flight can see him remain in the plans of new Oranje coach Guus Hiddink after being included in his first squad ahead of fixtures against Italy and Czech Republic next month.
Source : PA
Source: PA