The 29-year old midfielder has signed an 18-month deal with the R’s, reuniting with former Spurs boss Harry Redknapp.
"Obviously the fact that Harry was here made a big difference. He knows me well as a player,” Jenas told Sky Sports.
"There's a big challenge ahead and I want to be a part of it. There's no time to waste, we need to hit the ground running and get the wins, starting on Saturday (at home against Norwich City)."