John Jermyn may refer to:

• John Hervey, 7th Marquess of Bristol, aka John Jermyn
• John Wesley Jermyn, homeless street performer in Los Angeles
• John Jermyn (field hockey), Irish field hockey player

• 742 in Ireland
• 742 in poetry
• 742 (number)
• 743 Eugenisis
• 743 in Ireland
• 743 in poetry
• 743 (number)
• 744 Aguntina
• 744 (New Jersey bus)
• 744 (number)
• 745 BCE
• 745i
• 745 Mauritia
• 745 (number)
• 746 Marlu
• 746 (New Jersey bus)
• 746 (number)
• 747 (1998 Kent song)
• 7472 Kumakiri
• 747-300
• 747-400
• 747-400ERF
• '74-'75
• 747-8
• 747-800