QPR are currently bottom of the Championship, but they could now potentially join near neighbours and FA Cup third round opponents Chelsea in the transfer market, should Mittal wish to spend his cash.
"The family is excited about becoming involved with QPR," said Mittal's son-in-law, Amit Bhatia.
"As a family, we love sport and particularly enjoy English football, and alongside Bernie and Flavio, we hope that we can improve the club's performance, with the ultimate ambition of a place in the Premier League."