Fourth dimension may refer to:

• Time in physics, the continued progress of existence and events
• Four-dimensional space, the concept of a fourth spatial dimension
• Spacetime, the unification of time and space as a four-dimensional continuum
• Minkowski space, the mathematical setting for special relativity

• Fourth dimension in art

• The Fourth Dimension, a 1988 experimental film by Zbigniew Rybczyński
• The 4th Dimension (film), a 2008 film
• The Fourth Dimension (film), a 2012 film made up of three segments, each with a different director

• Fourth dimension in literature
• The Fourth Dimension (book), a 1984 non-fiction book by Rudy Rucker
• The Fourth Dimension, a book by David Yonggi Cho
• The Fourth Dimension, a book by P. D. Ouspensky

• The Fourth Dimension (Hypocrisy album), 1994
• The Fourth Dimension (Jack McDuff album), 1974
• Fourth Dimension (Stratovarius album), 1995
• Fourth Dimension (Radiophonic album), by Paddy Kingsland
• Fourth Dimension Records, a UK record label
• "The 4th Dimension", a song by Devo on their album Shout
• "Fourth Dimension", a song by Lights on her album Siberia
• 4th Dimension, a jazz fusion quartet founded in 2007 by John McLaughlin
• "4th Dimension" (song), a song by Kids See Ghosts on their 2018 album Kids See Ghosts

• The Fourth Dimension (company), a publisher of computer games
• 4th Dimension (software), a relational database management system

• Four-dimensionalism, a philosophical view
• 4th Dimension roller coaster, a type of roller coaster

• 4D (disambiguation)
• Four Dimensions (disambiguation)