The musician, from Kingston, Jamaica, was a founding member of The Wailers alongside his childhood friend, Bob Marley.
Together, they achieved international fame with reggae classics like Simmer Down and Stir It Up, before Wailer left to go solo in 1974.
He went on to win three Grammys and was given Jamaica's Order Of Merit in 2017.
His death was confirmed by manager Maxine Stowe, and Jamaica's Culture Minister, Olivia Grange.
The cause of death is unknown, but he had been in hospital since having a stroke in July 2020.
Tributes have already poured in for the musician, with fans and fellow musicians describing him as a legend.
"Oh man, god bless Bunny Wailer," wrote Red Hot Chili Peppers bassist, Flea. "What a true rocker and noble man. I love him."
Andrew Holness, Jamaica's prime minister, also paid tribute, calling his death "a great loss for Jamaica and for reggae".
The star, whose real name was Neville O'Riley Livingston, had been the last surviving member of The Wailers, following Bob Marley's death from cancer in 1981, and Peter Tosh's murder during a robbery in 1987.
Born on 20 April 10, 1947, Livingston spent his earliest years in the village of Nine Miles, where he was raised by his father, Thaddeus, who ran a grocery store.
That was where he first met Marley, and the toddlers soon became firm friends, making their first music together at Stepney Primary and Junior High School.
Following the death of Marley's father in 1955, his mother, Cedella, moved in with Livingston's father. The boys were essentially raised as step-brothers, especially after Cedella and Thaddeus had a daughter together, Pearl.
After moving to Trenchtown in Kingston, they met Peter Tosh and formed a vocal group called The Wailing Wailers - because, Marley said: "We started out crying."
The area was poor and afflicted by violence. Livingston later remembered building his first guitar from "a bamboo staff, the fine wires from an electric cable and a large sardine can".
But singer Joe Higgs, aka "the Godfather of Reggae", lived nearby and took the boys under his wing. Under his tutelage, they refined their sound, adding vocalist Junior Braithwaite and backing singers Beverly Kelso and Cherry Green before shortening their name to The Wailers.
In December 1963, the band entered Coxsone Dodd's infamous Studio One to record Simmer Down, a song Marley had written calling for peace in the ghettos of Kingston.
Faster and harder than the music The Wailers later became known for, the song was an immediate hit, reaching number one in Jamaica. They followed it up with the original version of Duppy Conqueror, before releasing their debut album The Wailing Wailers, in 1965.