The decision Tuesday means the former football star must remain in a Nevada state prison where he is serving nine to 33 years for armed robbery and kidnapping in a bungled attempt to retrieve personal items from two sports memorabilia dealers in 2007.
Simpson was sentenced to prison in 2008. He'll be 70 years old before he is eligible for parole.
Simpson's current defense attorneys argued that his previous lawyers handled his case so badly that he should get a new trial.
Clark County District Court Judge Linda Marie Bell considered 22 claims of ineffective assistance of counsel and attorney conflict of interest, but decided in her 101-page order that the standard required for a new trial wasn't met.