The 26-year-old had been linked with a number of clubs during the transfer window, including Tottenham, West Ham, Newcastle and Crystal Palace, after scoring 18 goals in the Premier League last season for Rangers.
But he tweeted on transfer deadline day: "#9 #QPR big season ahead."
Austin's current contract at QPR is due to expire in the summer of 2016.
Former Burnley forward Austin also made a statement on Twitter earlier in the window to rebuff comments from West Ham co-owner David Sullivan which claimed the striker's fitness would make the signing a risk.
The player labelled the claims as an "outrageous slur" and Sullivan later apologised.