The Moroccan international spent last season on loan at Loftus Road and has now put pen to paper on a three-year deal with the npower Championship side.
Taarabt, 21, was hailed as the "new Zinedine Zidane" when he arrived at White Hart Lane from Lens for £3million in 2007, but he made just nine appearances for Spurs - who are taking a significant loss on the midfielder Harry Redknapp once described as "frightening".
I'm glad to have finally tied Adel up," said Rangers boss Neil Warnock.
"He's a player who has got a unique talent and I'm hoping that we can channel it for the good of QPR.
"I've been very patient and I've probably worn him down over the past few months! We're delighted to have him on board and he gives us that little bit of quality that you need.
"I think it's good for him that he knows where he's going to be permanently now. Long term, his target is still to play at the very top level, and I'm hoping that we can help him to achieve that."
Taarabt hit seven goals for Rangers last term but at times still found himself out of the first team until Warnock arrived in March.
He said: "I'm delighted to be back. I had options to go elsewhere, but what Neil said to me was very positive and I've made the decision to join QPR.
"This is the first time in my life that I've had ambition. Before, I'd play football just to enjoy it, but now I've come to an age where I have to step up."
Source: PA
Source: PA