The Melbourne gangland killings were the murders of 36 underworld figures in Melbourne, Victoria, Australia, between January 1998 and August 2010. The murders were retributive killings involving underworld groups. The deaths caused a power vacuum within Melbourne's criminal community, and rival factions fought for control and influence. Many of the murders remain unsolved, although detectives from the Purana Taskforce believe that Carl Williams was responsible for at least ten of them. The period culminated in the arrest of Williams, who pleaded guilty on 28 February 2007 to three of the murders.

Since the confession of Williams, the ultimate source of the violence has become public knowledge. On his 29th birthday, while meeting with Jason Moran and his half brother Mark Moran on 13 October 1999 at a suburban park in Gladstone Park, Jason Moran shot Carl Williams in the stomach over a dispute about money relating to their amphetamine trade. Through the period after his run-in with the Moran family, Williams commenced a war with the aim of killing all members of the ‘Carlton Crew’.

The murder of former lawyer Mario Condello on 6 February 2006 caused speculation of a possible resurgence in the killings, although this was denied by police.

On 19 April 2010, Carl Williams was murdered by fellow inmate Matthew Johnson while incarcerated at Barwon Prison. Williams would have been 71 before becoming eligible for parole.