The visitors made the perfect start and opened the scoring inside the first two minutes. Debutant Stephen McLaughlin slid an inch-perfect pass through for Matt Derbyshire, who calmly slotted an effort past Jack Butland.
They continued to dominate and Derbyshire scored his second of the afternoon in the 16th minute after rounding Butland and sliding the ball into the empty net.
McLaughlin threatened from range just after the hour-half mark, but his strike from distance was held by the keeper.
Ross McCormack was inches away from pulling a goal back for Leeds shortly before half time when his curling free kick went wide of the post.
The midfielder threatened again from a set piece after the break, but Dorus de Vries kept out his strike.
McCormack looked the man most likely to bring Leeds back into the game and fired a volley over the bar after latching onto a knockdown inside the box.
Leeds almost found the net in the 78th minute when Danny Pugh's cross from the left came back off the crossbar.
The hosts continued to push for a goal but could not find the net as Forest moved to within one point of top six in the Championship table.