John Hennessey
John Hennessey or Hennessy may refer to:
Religious figures
- John Hennessy (bishop), American Roman Catholic archbishop of Dubuque, Iowa
- John Joseph Hennessy, Irish-born prelate of the Roman Catholic Church in Kansas
Sportspeople
- John F. Hennessey, American tennis player
- John Hennessey (rugby league), Welsh rugby league footballer
- John Hennessy (American football), American football player
- Jackie Hennessy, Irish footballer
Others
- John Pope Hennessy, Governor of Hong Kong, grandfather of John Pope-Hennessy
- John David Hennessey, English-Australian author, newspaper editor and Protestant minister
- John A. Hennessy, American special investigator
- John W. Hennessey Jr., American academic and educator
- John Pope-Hennessy, British art historian and museum director, grandson of John Pope Hennessy
- John J. Hennessey, American four-star army general
- John L. Hennessy, American computer scientist; former president of Stanford University
- John M. Hennessy, American financier and philanthropist