Lukas Nmecha opened the scoring at the City Ground, sparking hope it would be an away day to savour for the travelling supporters.
However, a disjointed display from the Whites enabled Forest to roar back with goals from Ibrahim Sangare, Morgan Gibbs-White and Elliot Anderson.
The loss has left Leeds just one point above the relegation zone, sitting precariously in 16th.
Basement boys Wolverhampton Wanderers beaten 3-0 by Chelsea as the club continue to hold talks with Middlesbrough head coach Rob Edwards.
West Ham United edged past Burnley in a meeting of two struggling sides, while Everton defeated Fulham and Sunderland held Arsenal to a 2-2 draw.
It was also level in a four-goal thriller between Tottenham Hotspur and Manchester United, who served up drama with late goals.
Aston Villa completed a 4-0 rout of AFC Bournemouth, Brentford came from behind to see off Newcastle United and it finished goalless between Crystal Palace and Brighton & Hove Albion.
The weekend of Premier League action was rounded off at the Etihad Stadium, where Manchester City swept Liverpool aside in a 3-0 win.
Following the latest results, here is how the Casino Hawks supercomputer expects the final Premier League table to look.
