Jasveen Sangha - Dec. 10
Jasveen Sangha, who's been branded as the "Ketamine Queen," pleaded guilty to five federal charges in September, including providing the ketamine that led to Perry's death.
She was the fifth and final defendant charged in Perry's overdose death to admit guilt.
Sangha is scheduled to be sentenced on Dec. 10. She could get up to 65 years in prison.
Dr. Salvador Plasencia - Dec. 3
Dr. Salvador Plasencia, who pleaded guilty in July, had been a primary target of the investigation alongside Sangha.
His sentencing hearing is set for Dec 3.
Dr. Mark Chavez - Dec. 17
Dr. Mark Chavez is one of three other defendants who pleaded guilty in exchange for their cooperation, which included statements implicating Sangha and Plasencia.
His sentencing hearing is set for Dec 17.
Erik Fleming - Jan. 7
Erik Fleming, the alleged middleman, is set to be sentenced on Jan. 7.
Kenneth Iwamasa - Jan. 14
The sentencing hearing for Kenneth Iwamasa, Perry's personal assistant, is set for Jan. 14.
Their potential maximum sentences range between 10 and 65 years in prison.
Perry was found dead in his Los Angeles home by Iwamasa. The medical examiner ruled that ketamine, typically used as a surgical anesthetic, was the primary cause of death.
Perry had been using ketamine through his regular doctor as a legal, but off-label, treatment for depression, which has become increasingly common. The actor struggled with addiction for many years, dating back to his time on "Friends," when he became one of the biggest stars of his generation as Chandler Bing.
He starred alongside Jennifer Aniston, Courteney Cox, Lisa Kudrow, Matt LeBlanc and David Schwimmer for 10 seasons from 1994 to 2004 on NBC's megahit series.
The Associated Press contributed to this report.