The Cape Grim massacre refers to an attack on 10 February 1828 at a beach in the north-west of Van Diemen's Land (Tasmania), now known as Taneneryouer (formerly Suicide Bay). A group of Aboriginal Tasmanians, believed to be from the Peerapper clan, were gathering muttonbirds and shellfish near an island outcrop known as The Doughboys when they are said to have been surprised and shot by four Van Diemen's Land Company (VDLC) shepherds. Some bodies were reportedly thrown from a cliff approximately 60 metres (200 ft) high. Death toll estimates vary widely across sources: convict Charles Chamberlain and an unnamed Aboriginal woman both told investigator George Augustus Robinson that around 30 people were killed, while VDLC Chief Agent Edward Curr initially reported six dead, and later revised this to three in a letter to Governor George Arthur.
The massacre occurred amid escalating conflict between the VDLC and Aboriginal clans of the North West nation, conflict historians trace partly to the abduction and rape of Aboriginal women by sealers and company workers. The immediate triggers were a December 1827 clash in which a shepherd was speared after Peerapper women were lured into a hut, followed by a Peerapper raid that destroyed 118 company sheep on 31 December 1827, and a subsequent punitive night raid in which VDLC ship captain Richard Frederick reportedly helped shepherds kill 12 men at a Peerapper camp.
News of the killings did not reach Governor Arthur for nearly two years. It surfaced only after VDLC agricultural superintendent Alexander Goldie wrote to Arthur in November 1829, describing his own involvement in Aboriginal killings and referencing the earlier events at Cape Grim. Arthur dispatched Robinson, who held an unofficial role as Aboriginal conciliator, to investigate. In June 1830, Robinson interviewed convict shepherd Charles Chamberlain, who admitted involvement and estimated 30 deaths, describing bodies being thrown "down the rocks where they had thrown the sheep." Robinson also interviewed a group of Aboriginal women who corroborated the account, and later spoke with a second shepherd, William Gunchannon, who admitted presence but was reluctant to detail the killings, reportedly saying he would "shoot them whenever he met them." The other two shepherds involved were not interviewed by Robinson: one had drowned and the other had relocated to Hobart.
Curr's own account to VDLC directors differed sharply from Robinson's findings, describing the shepherds as acting in self-defense against an advancing party they believed intended to attack. Historians examining the case, including Ian McFarlane, have argued Curr's version is implausible given the site's terrain and the shepherds' likely tactical position. Author Keith Windschuttle has disputed the scale of the massacre or its occurrence in the form described by Robinson, based on his own site inspection and arguing the terrain made a surprise attack and mass killing implausible.
The exact clan affiliation of the victims remains uncertain given the presence of multiple tribes in the area at the time, though historian Lyndall Ryan identifies them as members of the Peerapper clan. The massacre is considered part of the broader "Black War" period of conflict between British colonists and Aboriginal Australians in Tasmania.