The annually-published list ranks Mittal above last year's leader, Manchester City owner Sheikh Mansour bin Zayed al Nahyan, who has a fortune of £17billion.
Mittal has largely taken a back seat to owners Flavio Briatore and Bernie Ecclestone since investing in QPR in December 2007 but he would appear the real financial power at the club.
Formula One supremo Ecclestone, however, is ranked eighth in the list with £1.466billion.
Third is Chelsea owner Roman Abramovich with £7.8billion - an increase of £800million on his position last year.
That rise is more than the Russian's total outlay at Stamford Bridge since his takeover in 2003.
Arsenal shareholders Stan Kroenke (£2.709billion) and Alisher Usmanov (£1.3billion) are fifth and ninth respectively. The Glazer family, owners of Manchester United, are seventh with £1.75billion.
David Beckham is in a league of his own in terms of player value, with a fortune of £125million.
The England and Los Angeles Galaxy midfielder is well clear of Manchester United pair Michael Owen (£38million) and Wayne Rooney (£37million).
Two more United players, Rio Ferdinand (£30million) and Ryan Giggs (£24million), make up the top five.
England boss Fabio Capello is the richest manager with £30million ahead of Roy Keane (Ipswich) and Sir Alex Ferguson (Manchester United) with £27million and £22million respectively.