Phillips, signed for an undisclosed fee, will not be available for the next few weeks as he continues his recovery from an arm operation.
Phillips told QPR's website: "QPR are a club with huge ambition.
"The direction in which the club is heading, with the signings that have already been made this summer, it seems like the perfect time to come here.
"We all know what Harry Redknapp is about and personally I can't wait to play for him. I've had a taste of the Premier League and nothing would please me more than to help get QPR back into the top flight.
"I'm very excited to be here and relishing the opportunity to play for the club."
Phillips becomes Redknapp's sixth signing of the summer, following Richard Dunne, Gary O'Neil, Danny Simpson, Charlie Austin and Karl Henry.
Redknapp said: "Matt's got a big, big future ahead of him in the game, so we're delighted we've been able to get him here.
"I like having wingers in my teams and he's very direct. He can take people on and make things happen. He's quick, he gets at people, he can make goals and he can score goals.
"He gets people off their seats and that's what you want to see as a supporter. He's a really exciting signing for us."
Phillips was born in Aylesbury and represented England at U19 and U20 levels but qualifies to play for Scotland and was handed his first cap last year.