Prosecutors said the assassination was part of a coup attempt led by Colonel Eddy Kapend, Kabila’s closest personal aide, and a court sentenced him and more than two dozen others to death.
The men were jailed and officials say a number have since died in prison, but none of the death sentences were carried out.
President Felix Tshisekedi pardoned the men – and a number of other people convicted in other cases – to show “humanity, pardon, justice and national reconciliation,” state television reported on Thursday night.
Human rights groups, the Catholic church and others had criticized the assassination trial as unfair.
Laurent Kabila’s death further scarred a country with a dark history of political assassinations, including the 1961 killing of its first post-independence prime minister, Patrice Lumumba, by secessionist rebels with support from Belgian officials.
Kabila’s son Joseph, who succeeded him, repeatedly resisted calls to pardon Kapend and the others. Joseph Kabila stepped down as president in 2019, and was replaced by Tshisekedi, a longtime opponent.
Tshisekedi governed for the first two years of his presidency in coalition with Joseph Kabila’s allies, but is now trying to distance himself from his predecessor and remove Kabila loyalists from the government.