The Death Eaters are a fictional extremist group from the Harry Potter series, led by the dark wizard Lord Voldemort. They follow a strict belief in blood purity, thinking that only pure-blood wizards should have power over the wizarding world. Because of this, they feel it is their duty to eliminate wizards born to non-magical families to keep their bloodline pure.

The Death Eaters have a symbol called the Dark Mark, which is a skull with a snake coming out of its mouth. This mark is placed on their left arm and can be used by Voldemort to summon them at any time. The mark burns to signal the call of Voldemort. It also helps them recognise each other. To hide their identities, Death Eaters usually wear black hooded robes and masks.

In the timeline of the Harry Potter series, the Death Eaters were formed as Voldemort's army during the First Wizarding War. During this time, their activities focused on fighting against the Ministry of Magic and the Order of the Phoenix, the two main opposing groups. They used attacks and threats against their enemies and their families to create fear and weaken their resistance.

The Death Eaters were first introduced as a group in the novel Harry Potter and the Goblet of Fire (2000). However, individual members such as Severus Snape, Lucius Malfoy, and Peter Pettigrew appeared in earlier books. The name of the group is only mentioned from the fourth book onward, but Voldemort’s followers are talked about in Harry Potter and the Philosopher's Stone and in Harry Potter and the Chamber of Secrets. The term "Death Eaters" is directly mentioned for the first time in Harry Potter and the Prisoner of Azkaban.

According to J.K. Rowling's speech at the 2007 Carnegie Hall event, the Death Eaters' beliefs are similar to the extremist ideas of the Nazi party. This is seen as a way to criticise racism and totalitarianism.

The Death Eaters first existed over 11 years before the events of the Harry Potter novels, torturing and murdering Muggles (non-magical people), as well as anyone who opposed them. When a deadly curse from Voldemort rebounded off Harry Potter and disembodied the Dark Lord, the Death Eaters largely disbanded and vanished.

Early in Harry Potter and the Goblet of Fire, a group of Death Eaters gathers at the Quidditch World Cup, which spreads chaos and fear amongst the wizarding community. Voldemort regains his full strength at the end of Goblet of Fire, and summons his followers to him.

The Minister for Magic, Cornelius Fudge, deluded himself into believing that Voldemort could not have come back and that it was all a lie cooked up by Dumbledore, who Fudge believed had designs on his political office. The Death Eaters use this tactical advantage throughout Harry Potter and the Order of the Phoenix to maintain their secrecy. Because of the Ministry's refusal to remove the Dementors from Azkaban, which Dumbledore advised immediately following Voldemort's return, the Death Eaters recruited the Dementors to their cause and made similar progress with the giants; the Dementors' revolt against the Ministry of Magic also allowed the Death Eaters to bolster their ranks with the mass break-out of several imprisoned Death Eaters, including Bellatrix Lestrange.