The ruling on Monday comes months ahead of parliamentary elections expected to be held in early February. The maximum punishment under the law that governs the tribunal is the death penalty.
Hasina's Awami League party has been barred from contesting and it is feared the verdict could stoke fresh unrest ahead of the vote.
The International Crimes Tribunal, Bangladesh's domestic war crimes court located in the capital Dhaka, delivered the guilty verdict amid tight security and in Hasina's absence after she fled to India in August 2024.
The verdict can be appealed in the Supreme Court, but Hasina's son and adviser Sajeeb Wazed told Reuters on the eve of the verdict they would not appeal unless a democratically elected government took office with the Awami League's participation.
During the trial, prosecutors told the court that they had uncovered evidence of her direct command to use lethal force to suppress a student-led uprising in July and August 2024.
According to a United Nations report, up to 1400 people may have been killed during the protests between July 15 and August 5, 2024, with thousands more injured - most of them by gunfire from security forces - in what was the worst violence in Bangladesh since its 1971 war of independence.
Hasina was represented by a state-appointed defence counsel who told the court that the charges against her were baseless and pleaded for her acquittal.
Ahead of the verdict, Hasina dismissed the accusations and the fairness of the tribunal proceedings, asserting a guilty verdict was "a foregone conclusion".
Bangladesh has been tense ahead of the verdict, with at least 30 crude bomb explosions and 26 vehicles torched across the country over the past few days. There have been no casualties, however.
