The 40-year-old former Scotland international has been under pressure at Boundary Park for some time following poor form, but earned a stay of execution after masterminding a famous FA Cup victory over Liverpool last weekend.
However, eight defeats out of nine games in League One has left the Latics hovering above the relegation zone and Dickov has decided to quit after two and a half years in the job.
A statement on the club's official website read: "After yesterday's defeat to Walsall, Paul Dickov has decided that for the good of Oldham Athletic Football Club, it is best that he steps aside."
