Two second half goals from Latics were enough to seal all three points at a bitterly cold Highbury.
Carl Winchester's first goal of the season five minutes into the second half gave Latics the lead and just after the hour mark, Mike Jones' curling free kick secured all three points for Lee Johnson's men.
Fleetwood really should have taken the lead after only three minutes of the game old. Jamie Proctor played the ball over the top to an unmarked Antoni Sarcevic but he fired wide when one-on-one with Paul Rachubka.
Latics responded well and started to take a grip on the game. Carl Winchester was receiving a lot of the ball on the right hand side and shot wide a couple of minutes later.
The Northern Irishman was given freedom to cut inside and shoot on 10 minutes but Fleetwood stopper Chris Maxwell saved comfortably.
With Latics enjoying the more of the possession, striker Dominic Poleon, who started in attack, shot from 25 yards which exceeded the crossbar.
Only a minute later, pressure from the visitors almost resulted in the opening goal of the game but Mike Jones struck narrowly over the bar from 20 yards.
Just after the half hour mark, Winchester had the best chance to put Latics ahead. Brian Wilson crossed from the right hand side but the 21-year-old fired horribly wide from inside the box.
The supporters were really getting behind Athletic and Latics were responding on the pitch but were finding clear-cut chances hard to come by.
As half time drew closer, the defence had to be alive following some Fleetwood pressure. George Elokobi had to clear off the line from Josh Morris and seconds later, Rachubka turned the ball around the post after Gareth Evans shot goalwards.
Latics had a chance immediately after the restart to take the lead. Jones was fouled on the left hand side of the area, stepped up himself and fired towards the top corner but Maxwell saved well.
Athletic took the lead five minutes into the half courtesy of the impressive Winchester. He received the ball on the edge of the box, cut inside and fired past Maxwell into the top corner to give the visitors the lead.
The ascendancy was with Latics and they went in search of more. Poleon forced his way into the box two minutes later but fired just wide from ten yards.
Fleetwood were struggling to cope with the pressure Latics were putting them under and they were knocking on the door of a second goal.
That goal did come on 64 minutes through a superb free kick from Jones. Poleon's persistence won Latics a free kick 25 yards out and the midfielder curled the ball into the top corner to extend Latics' lead.
The home side were struggling to create chances of their own but on 70 minutes they went close to pulling a goal back.
Winchester conceded a foul on the edge of the box but Rachubka excellently tipped Evans' free kick over the bar as Latics stayed alert.
Rachubka had to be alert again ten minutes from time as Nick Haughton found space at the back post but the goalkeeper stood tall and tipped the ball around the post.
As the game drew to a close, Latics remained professional and saw the game out to the delight of the 1,285 travelling supporters who did not stop all afternoon.
The referee blew the final whistle which signalled the first win since the end of November.
Fleetwood Town: Maxwell, McLaughlin, Roberts, Evans, Dobbie (Haughton 56'), Hughes, Morris (McAlinden 56'), Sarcevic, Proctor, Jordan, Crainey (Ball 75').
Subs not used: Pond, Schumacher, Forbes, Springthorpe.
Oldham Athletic: Rachubka, Brown, Elokobi, J.Wilson, B.Wilson (Kusunga 83'), Jones, Kelly, Winchester (Dieng 89'), Philliskirk, Morgan-Smith, Poleon (Dayton 90+2').
Subs not used: Coleman, Lockwood, Jacobs.
Goals: Fleetwood Town 0-2 Oldham Athletic (Winchester 51', Jones 64')
Attendance: 4,312 (1,285 visiting supporters)