Graeme Murty's late penalty helped Championship champions Reading set a new league points record of 106.
Reading players celebrate Dave Kitson's opening goal
Murty's strike - only his second goal in 280 Reading appearances - ensured the Royals topped Sunderland's previous record of 105 in the 1998-99 season.
The Royals led thanks to Dave Kitson's 40th-minute tap-in after John Oster cut the ball back across the six-yard box.
Paul Furlong's drive on 72 minutes made it 1-1, but Murty secured the win with Reading's 99th goal of the season.
It was the 31-year-old club captain's first goal of the season and ended his record of being the only regular outfield starter yet to score for Reading during this campaign.
Reading fans were in celebratory mood from the start at the Madejski stadium, knowing that the club was on the verge of setting a new record for points - and just three goals short of a century.
They seemed to be on the way to achieving both goals when Kitson netted his 22nd goal of the season five minutes before the break for Steve Coppell's men.
Rangers' 25-year-old veteran Furlong looked to have spoiled the party somewhat, however, when he popped up with a smart finish to level with 18 minutes remaining.
But Murty's rare goal sparked wild celebrations in the stands and from his team-mates.
Reading manager Steve Coppell:
"You spend your life in football working for moments like this.
"It's true we fell one short of achieving 100 goals for the season but that's not really going to spoil my break when I am sitting on the beach and sinking a few beers.
"What I will reflect on is collecting the trophy on the pitch in front of the home fans. That really topped the season off."
QPR acting manager Gary Waddock:
"We decided to have a go at Reading and see how they coped with us.
"It will have been a good experience for our younger players.
"I'm planning for next season, somebody has to do it, but you will have to ask the chairman if I'll be the manager."
Reading: Hahnemann, Murty, Sonko, Ingimarsson, Shorey, Convey (Gunnarsson 85), Harper, Sidwell, Oster (Hunt 61), Doyle (Long 85), Kitson.
Subs Not Used: Stack, Makin.
Goals: Kitson 40, Murty 84 pen.
QPR: Paul Jones (Cole 45), Bignot, Shittu, Santos, Milanese, Ainsworth, Cook, Bailey (Ray Jones 68), Langley, Donnelly, Furlong.
Subs Not Used: Evatt, Munday, Howell. Goals: Furlong 72.
Ref: D Drysdale (Lincolnshire).