John Jacob is the name of:
- John Jacob Astor, first of the Astor family dynasty and first millionaire in the U.S.
- a U.S. administrator, see John Edward Jacob
- a General, see John Jacob (soldier)
- a candidate for U.S. Congress, see John D. Jacob
- a Marquess of Montferrat, ruling (1418-1445)
- nom-de-plume of former Amway executive Eric Scheibeler
- former West Virginia Governor John J. Jacob
