Delta 4 (disambiguation)
Delta 4 or variant may refer to:
- Delta 4 (developer) defunct British software developer
 - Delta IV (rocket) U.S. space rocket
 - Mission Delta 4, U.S. Space Force
 - Delta-class submarine including the Delta-IV subclass
 - Delta IV oil field in the Black Sea
 - Lippisch Delta IV, German experimental aircraft designed by Alexander Lippisch