Bob Marley won 0 competitive Grammy Awards during his lifetime.
Marley died in 1981, before the Recording Academy gave him a competitive Grammy win. The Grammy Award for Best Reggae Album was first presented in 1985, several years after his death, so he could not compete in that category while alive. His recordings nevertheless became central to reggae's Grammy history.
The number is often confused because Marley received major Grammy recognition after death. In 2001, he was awarded the Grammy Lifetime Achievement Award, a special-merit honor recognizing an artist's lasting contribution to recorded music. That award is not a competitive Grammy won for a particular album or song.
Other Marley-related Grammy references can also cause confusion. Tribute albums and recordings by family members or other artists have won Grammys, and albums such as Catch a Fire later entered the Grammy Hall of Fame. Those honors do not change Marley's competitive Grammy total during his lifetime: it remained zero.