Isaiah "Ike" Zimmerman (April 27, 1907 – August 3, 1967) was an American blues guitarist, who is now known to have been musician Robert Johnson's main guitar teacher.

Johnson stopped to visit a local juke joint, where he saw Zimmerman perform.

According to one of Zimmerman's daughters, interviewed by blues researcher Bruce Conforth:He [Robert].. he fitted in our family, and he had to be nice, because my daddy was a strong man and ...a good man, my daddy was, and so he wouldn’t have taken up no time with someone who wasn’t a good person.

After practising together while sitting on tombstones in Beauregard Cemetery – thought to be a contributory factor to the legend of Johnson "selling his soul to the Devil" in order to play well – the pair toured local lumber camps and juke joints before Johnson began performing on his own.

He moved to California around 1960, and died in Compton, Los Angeles, from a heart attack in 1967, aged 60.