Ricardo Vaz Te's first-ever goal for Bolton was enough to see his side into the FA Cup fifth round.
The young Portuguese star headed home from Ricardo Gardner's cross early on to ease the visitors' nerves.
Oldham keeper Les Pogliacomi had to make point-blank saves from Kevin Davies and Khaliou Fadiga, but the home side had chances of their own.
Bolton keeper Jussi Jaaskelainen saved from Daniel Hall, and Alex Bruce volleyed inches over.
But Bolton's afternoon was marred by a tackle on Nicky Hunt by Lee Croft that resulted in the defender limping off injured.
Oldham's hopes of repeating their third-round shock win over Manchester City were knocked as Bolton's goal came with the first meaningful attack of the game.
Just eight minutes were on the clock as Gardner crossed well from the left and Pogliacomi was unable to keep Vaz Te's header out despite getting a hand to the ball.
Oldham responded well to the disappointment, however, and John Eyre saw a shot blocked by Fernando Hierro before Neil Kilkenny claimed a penalty after a tackle from Bruno N'Gotty.
Mark Hughes also volleyed wide for the home side - but Bolton remained an attacking threat, and Khaliou Fadiga saw a shot blocked before Kevin Nolan shot wide.
The half ended in rather scrappy fashion, although Oldham's fans took some heart from the occasional shaky moment in the Bolton defence.
But it was the Premiership team who began the brighter in the second half, with Henrik Pedersen sending a snap-shot wide in the opening minutes.
Pogliacomi then made a superb reaction save from Kevin Davies on 53 minutes, as the striker prodded the ball goalwards from just four yards.
Bolton suffered a blow on 54 minutes, however, when Nicky Hunt was stretchered off after Lee Croft's crunching tackle.
Vaz Te almost netted his second seven minutes later as he connected with Pedersen's fine low cross from the left and sent the ball inches over the bar.
Oldham were struggling for opportunities, although Kilkenny sent a volley well wide of the target with 25 minutes remaining.
The home side came much closer on 72 minutes as Anthony Barness had to head behind his own goal following Kelvin Lomax's incisive cross.
But Fadiga should have put the result beyond doubt two minutes later as he broke clean through, only to see Pogliacomi save his shot, and Davies had his follow-up strike blocked.
Play opened up late on and Bolton had Jaaskelainen to thank as he saved from Hall.
And Oldham came even closer moments later as Bruce volleyed inches over after David Eyres' cross.
Still there was time for Griffin to test Jaaskelainen with a long-range effort but there was to be no late fairytale for Oldham.
Oldham boss Brian Talbot:
"The lads gave everything they had, the commitment was there, the effort was first class," he said.
"I'm biased, but our second-half performance merited something.
"We had chances in the second half and enough of the ball around their box to score. We wish Bolton good luck, what we must not do is let this affect us."
Bolton boss Sam Allardyce:
"I thought (Lee Croft) went over the top. I could see (Nicky) Hunt was going to win the ball.
"It's a shame in a game like this but I am not going to let that overshadow the professional performance from our side.
"It was a fantastic effort from Oldham. We needed a couple of good saves. It was a typical cup tie at this level."
Oldham: Pogliacomi, Griffin, Haining (Lomax 56), Bruce, Daniel Hall, Croft, Eyre (Cooper 72), Betsy, Hughes, Kilkenny, Eyres.
Subs Not Used: Appleby, Mildenhall, Lever.
Bolton: Jaaskelainen, Hunt (Barness 56), N'Gotty, Ben Haim, Gardner, Hierro, Vaz Te (Campo 81), Nolan, Fadiga (Diouf 89), Pedersen, Davies.
Subs Not Used: Poole, Laville.
Booked: Hierro, Ben Haim.
Goals: Vaz Te 9.
Ref: M Messias (S Yorkshire).