Phase 4, Phase IV or Phase Four may refer to:
Media Marvel Cinematic Universe: Phase Four, a group of superhero films and television series from 2021–2022 Phase IV (1974 film), a science-fiction horror film directed Saul Bass Phase IV (2002 film), a Canadian action-thriller film directed by Bryan Goeres 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