Media
* Marvel Cinematic Universe: Phase Four, a group of superhero films and television series beginning in 2021 * Phase IV (1974 film), ''Phase IV'' (1974 film), a 1974 film * Phase IV (2002 film), ''Phase IV'' (2002 film), a 2002 film * Phase IV (album), ''Phase IV'' (album), a 1982 album by Art Zoyd * Phase-4, a character in ''Dead or Alive 5 Ultimate''Other
* Phase IV clinical trial, the fourth of the phases of clinical research * Phase 4 Films, a Canadian film distribution company * Phase 4 Stereo, record label and recording process * Four-Phase Systems, a computer company * Four-phase logic, is a type of, and design methodology for dynamic logic {{Disambiguation