RRN can refer to:

• Relative record number
• Resident registration number
• Retrieval Reference Number, a key to uniquely identify a card transaction based on the ISO 8583 standard.
• Route reestablishment notification
• Run River North, a indie folk-rock band from Los Angeles, California.
• Rural Reconstruction Nepal, a social development NGO in Nepal.

• John Simon
• John Simon, 1st Viscount Simon
• John Simon Bercow
• John Simon (critic)
• John Simon Guggenheim Foundation
• John Simon Guggenheim Memorial Foundation
• John Simon Ritchie
• John Simpson
• John Simpson (journalist)
• John Simpson Kirkpatrick
• John Simpson Knox
• John Simpson (VC)
• John Sims (taxonomist)
• John Sinclair
• John Sinclair, 1st Baron Pentland
• John Sinclair (British spy)
• John Sinclair (poet)
• John Singer Sargent
• John Singleton
• John Singleton Copley
• John Singleton Copley, 1st Baron Lyndhurst
• John Singleton Copley, 1st Lord Lyndhurst
• John Singleton Copley, Baron Lyndhurst
• John Singleton Copley Lyndhurst
• John Singleton Mosby