Cheltenham scored twice in the second-half as Latics slipped to their first defeat in seven away league games.
Andy Williams and Alfie May were both on target to secure the points for the home side, leaving Oldham to reflect on a disappointing evening.
Harry Kewell’s side created enough chances to have taken the lead during a promising first-half display but were punished for failing to capitalise when on top.
Latics were the better side until Williams opened the scoring nine minutes after half-time, but once ahead Cheltenham were able to close out the game with a degree of comfort.
Laurence Bilboe, deputising in goal again for the injured Ian Lawlor, was called into a number of early saves, twice denying May in the opening minutes before saving Williams’ header from a Lewis Freestone cross.
Latics thought they had opened the scoring on 12 minutes, when Marcel Hilssner’s fiercely-struck free-kick from fully 40 yards was fumbled by Josh Griffiths. The ball looked to be inching in but referee Carl Brook judged that it had not crossed the line by the time the goalkeeper recovered.
A shot from Bahamboula flashed wide and the Frenchman had a golden chance shortly before the interval. He raced into the area having been released by a great pass from Hilssner but dwelt on the chance, meaning his shot was charged down.
McAleny curled a shot wide after good approach work involving Hilssner and Nicky Adams, and Latics’ bright play continued initially after the re-start with McAleny’s shot being deflected wide.
It was against the run of play that the home side went ahead, Williams sending a curling effort past Bilboe and the home side proceeded to take control.
That was not until Bahamboula, weaving his way in from the right, sent a shot against the Cheltenham crossbar, but that was as good as things would get the for visitors.
Boyle headed wide from a Clements corner, while Bilboe gathered a Finn Azaz shot at the second attempt and the goalkeeper did well to deny Williams at close range.
By now, the home side were firmly in the ascendancy and any chance of a Latics comeback was extinguished on 83 minutes when May found the target after a nice turn and excellent finish.
Cheltenham Town: Griffiths, Tozer, Raglan, Thomas, Clements, May (Lloyd 85), Blair, Williams (Addai 90), Boyle, Freestone, Azaz.
Subs not used: Flinders, Long, Bowry, Chamberlain, Ebanks.
Oldham Athletic: Bilboe, Clarke, Jombati, Garrity, Keillor-Dunn (McCalmont 76), Jameson (Badan 70), Ntambwe (Grant 64), McAleny, Hilssner, Adams, Bahamboula.
Subs not used: Chapman, Piergianni, Fage, Hamer,
Referee: Carl Brook