QPR vice-chairman Amit Bhatia has resigned following disagreements with the club's board.
He quit on the day it was revealed fans will be charged up to £72 to watch a Premier League match next season.
Bhatia said he strongly disagreed with the price increases to season tickets.
Bhatia also revealed that the Mittal family had failed in its bid to buy the club from fellow co-owners Bernie Ecclestone and Flavio Briatore.
Bhatia joined the Loftus Road board in December 2007 as representative of father-in-law Lakshmi Mittal after the Indian steel magnate bought a shareholding alongside Ecclestone and Briatore.
However, Bhatia has grown disillusioned of late, revealing the sacking of former chairman Ishan Saksena and a near 40% increase in season ticket prices following promotion to the Premier League had forced him to stand down.
In a letter to the club's board seen by the BBC, Bhatia said: "It is clear to me from recent board meetings that my vision, strategy and direction for the club is very different from that of the other shareholders and board members.
"The recent decisions to sack club CEO and chairman Ishan Saksena and significantly increase season ticket prices are just two of the decisions I disagree with.
"While it saddens me to leave QPR after such a successful season and at the beginning of an exciting new phase, I do not wish to be associated with or take responsibility for decisions made by the board and with which I disagree so strongly.
"The Mittal family had been in discussions concerning the possible acquisition of the club. However, we have been unable to reach agreement on this matter and therefore those discussions have now come to an end.
"Although no longer a decision-maker at QPR, I shall continue to be a 33% owner and a 100% fan of the club. In due course, we will appoint a board representative to monitor my family's investment in the club."
QPR have defended the price hike in season tickets.
"The board is keen to stress that the prices are in line with other London-based Premier League Clubs, and are encouraged by early sales figures following the release of season tickets earlier on Tuesday," said a club statement.
QPR fans will be charged up to £72 a game for their first season back in English football's top flight.
The cheapest price for a league match at Loftus Road will be £47, with season tickets up by almost 40%.
But with five fewer home games in the top flight, the increase is around 67% in real terms.
Paul Finney, of the Independent Rs website, said of the news: "It's an absolute disgrace.
"Yet again it underlines the total contempt the owners of QPR have for the fans. Flavio Briatore's dream is a 'boutique' club, which has an exclusive feel to it and is the place for wealthy people to be seen.
"Not only is that a slap in the face of QPR supporters, it is not in the long-term interests of a club that has two other Premier League clubs [Chelsea and Fulham] on its doorstep."
The cheapest adult season ticket for the new campaign will be £549, with £999 the most expensive - up from £699 in last year's Championship winning season - while under-16s will be charged £199 and under-eights up to £99.
By comparison, the cheapest season ticket at Manchester United is £513. At Arsenal it is £893 and at Blackburn £225, the most and least expensive in the top flight respectively.
Rangers fan Clive Whittingham, who runs the Loft For Words website, said the club was in the position of knowing that, with only 15,000 home seats to fill, it could charge what they like for tickets and still sell them all.
"The worst thing about it, apart from the scandalous walk-up fees which again come back to not having many seats to sell, is the lack of reward for loyalty," he said. "As a season ticket holder of 18 years standing, I am receiving no discount for renewing."