Tim Cahill's fourth goal in three games sent high-flying Millwall into the top six and pushed Wimbledon's kids closer to the drop.
The defeat leaves Wimbledon 24 points shy of safety with just ten games left.
Cahill backed up his brace against West Ham on Sunday with a six-yarder just before the break after Kevin Muscat had brought the ball from the Lions' own half.
Aussie hotshot Cahill had the ball in the net six minutes from time but the goal was ruled out for a foul on defender Mark Williams.
And Danny Dichio should have added one for the Lions on 65 minutes when he skinned golden oldie Warren Barton only to blast high into the West Stand.
Nico Herzig missed the Dons' best chance of breaking their three-month scoring duck just seven minutes into the match when his header was easily palmed over the bar by Lions keeper Andy Marshall.
And the Wimbledon defence was repeatedly stretched by speedy midfielders Cahill and Paul Ifill - who should have put the visitors up after six minutes.
Millwall, who kept the same side that hammered West Ham on Sunday, could have gone ahead after just 42 seconds, but Neil Harris blasted Ifill's cross over the bar.
Ifill almost had one of his own soon after when he waltzed past Wimbledon's back four only to fire straight into the hands of keeper Scott Bevan.
Lions player-boss Dennis Wise came on to a chorus of boos to face his old club in the 18th minute after David Livermore hobbled off following a collision with team-mate Dichio.
And he was immediately in the thick of the action, putting through for Dichio to fire a rocket which was parried by Bevan.
But there was little to please the chilly souls scattered in the home stands as the Dons struggled to contain the Lions quick-fire passing game.
Wimbledon gave right-winger Ifill far too much space and he was repeatedly allowed to dribble his way up the entire length of the pitch.
It was only the stout defending of Mark Williams that kept the Dons in the game for much of the first half.
Albert Jarrett was one of the few shining lights in Wimbledon's attack and he did well to beat Aussie hardman Muscat and fire into the box, only to be let down by Wayne Gray's wayward shots.
But winger Jarrett only had 36 minutes to shine before he was taken off in favour of Middlesbrough loanee Gary Smith.