Robert "Bob" Weir (born October 16, 1947) is an iconic American musician and songwriter, best known as a founding member and rhythm guitarist of the legendary Grateful Dead. His musical journey began after a serendipitous meeting with Jerry Garcia on New Year's Eve 1963, which led to the formation of the Grateful Dead, a band profoundly influenced by The Beatles' transition to rock 'n' roll. Throughout the Grateful Dead's three-decade career, Weir contributed distinctive rhythm guitar work and sang many lead vocals, developing a "quirky, whimsical" playing style praised for its keyboard-like chord voicings.

After the Grateful Dead disbanded in 1995, Weir continued his prolific career, forming and performing with several notable bands including RatDog, Furthur (co-led with Phil Lesh), and most recently Dead & Company, alongside John Mayer. His significant impact on music has been widely recognized, leading to his induction into the Rock and Roll Hall of Fame in 1994 and the prestigious Kennedy Center Honors in 2024, both as a member of the Grateful Dead.