Striker Paul Warne was sent off for the home team on 31 minutes and there was no way back as the Latics suffered a third straight defeat in Coca-Cola League One.
Badly hit by five injuries in central defence, Oldham struggled to contain a lively Huddersfield team who put their promotion bid back on track.
Taylor-Fletcher and Danny Schofield were clinical in front of goal while Oldham's strikers were wasteful at the other end.
Oldham could have got in front after 16 minutes when Andy Liddell rounded Town keeper Paul Rachubka but saw his shot from 18 yards cleared off the line by Tom Clarke.
And they were made to pay when Huddersfield opened their account 11 minutes later. Jonathan Worthington broke from midfield and after his shot was saved by Chris Day, Schofield pounced to slide it home.
Oldham's problems soon increased when Warne received a straight red card for leading with his elbow while jumping for a high ball with Huddersfield right-back Andy Holdsworth.
Oldham were unhappy with the decision but Huddersfield rubbed salt into the wounds when Clarke crossed to the far post and Taylor-Fletcher headed in from close range.
It was almost 3-0 on 48 minutes but Pawel Abbott, looking for his eighth goal in nine games, hit the bar from 20 yards.
Oldham's chance to launch a comeback was wasted by midfielder Richie Wellens and substitute Chris Porter who both headed off target.
Huddersfield finished off the game after 73 minutes when Abbot played in Taylor-Fletcher for a cool finished from 10 yards into the far corner.