4.0

4.0 may refer to:


 * 4 (disambiguation)
 * 4.0 (Mónica Naranjo album), a 2014 compilation album by Spanish recording singer-songwriter Mónica Naranjo
 * LP Underground 4.0, a 2004 CD and digital download set by Linkin Park Underground
 * Live Free or Die Hard, a 2007 American action thriller film (released as Die Hard 4.0 outside North America)