The Great Sith War was a conflict fought between the Jedi Order and Sith prior to the Jedi-Sith War, which took place in around 1032 BBY. According to Jedi Master Oppo Rancisis, the Jedi won the war. In 232 BBY, Rancisis cited the Jedi's victory in the war during a Jedi High Council debate over whether the Order was obliged to assist the Republic Defense Coalition in hunting down the Nihil raiders. Ultimately, the vote was narrowly decided in favor of Jedi participation, leading to the Battle of Kur.
The Great Sith War was canonically mentioned in the 2021 novel The High Republic: Light of the Jedi, written by Charles Soule. In the Star Wars Legends continuity, the Great Sith War first appeared in Tales of the Jedi 2, a comic part of the Tales of the Jedi series, published on November 16, 1993, written by Tom Veitch, drawn by Chris Gossett, and edited by Dan Thorsland. Although not confirmed to be the same conflict, the 2016 sourcebook for the Star Wars: Force and Destiny role-playing game, Nexus of Power includes a great number of similarities to the Legends Great Sith War, including Ulic Qel-Droma, and Exar Kun, both central figures in the Legends Great Sith War.