John Harmon may refer to:

• John Harmon (actor) (1905–1985), American actor
• John Harmon (attorney) (born 1944), United States Assistant Attorney General under President Jimmy Carter
• John Harmon (coach), Boston University basketball and football coach
• John Harmon (character), a character in Our Mutual Friend
• John H. Harmon (1819–1888), mayor of Detroit and publisher of the Detroit Free Press

• Lights On (Katy B song)
• Lights On The Hill
• Lights on the Hill (song)
• Light sources
• Lights-Out
• "Lights Out"
• Lights Out (1946 TV series)
• Lights Out (2010 film)
• Lights Out (2011 TV series)
• Lights Out (antimatter)
• Lights Out (Breaking Benjamin song)
• Lights Out (Danity Kane song)
• Lights Out (disambiguation)
• Lights out for darker skies
• Lights Out Puzzle
• Lights Out (Rick Astley song)
• Lights Out (Santigold song)
• Lights Out (Santogold song)
• Lights Out (single)
• Lights Out (song)
• Lights Out! the game
• Lights Out (TV series)
• Lights Out (video game)
• Lightspark
• Lightspeed (album)