Brentford secured their sixth successive home win thanks to goals from Isaiah Rankin and Deon Burton. The first goal came when Rankin latched on to a long clearance and turned to poke home the ball low into the corner.
Jamaican international Deon Burton guaranteed the points a minute after the restart when he powered home a header from Jay Tabb's precision cross.
Rankin almost made it three late on when he skipped past three challenges to curl a drive just wide of the post.
Brentford: Nelson, O'Connor, Turner, Sodje, Frampton, Tabb, Talbot, Hargreaves (Lawrence 74), Salako (Hunt 63), Burton (Harrold 72), Rankin.
Subs Not Used: Myers, Julian.
Booked: Hargreaves.
Goals: Rankin 45, Burton 47.
Oldham: Mawson, Holden, Haining, Arber, Griffin (Jack 55), Betsy, Boshell (Lomax 55), Eyre, Eyres (Appleby 55), Johnson, Killen.
Subs Not Used: Pogliacomi, Barlow.
Booked: Johnson.
Att: 5,818.
Ref: A Hall (W Midlands).