J4

• 4J (disambiguation)
• ATC code J04
• Airmak J4
• Auster J-4
• Buffalo Airways
• College Park–Bethesda Line
• County Route J4 (California)
• GNR Class J4
• Great Southern and Western Railway
• Grumman Widgeon
• HMAS J4
• JAC J4
• Janko group J4
• Junkers J 4
• League of Legends
• Mikoyan-Gurevich MiG-17
• Morris Commercial J4
• Peterson J-4 Javelin
• Piper J-4
• S/2003 J 4
• Samsung Galaxy J4
• Square cupola