Karami, who hailed from the northern city of Tripoli, died at the American University of Beirut's medical center following a long battle with illness.
The Karami family announced the veteran politician's death in the early hours of Thursday.
Born in 1934, Karami served as Lebanon's prime minister twice, from 1990 to 1992 and from 2004 to 2005. He stepped down along with the government after the assassination of former prime minister Rafic Hariri triggered mass protests.
He was also elected to parliament three times – in 1992, 1996 and 2000.