IV

IV may refer to:

In the United States

 * Immigration Voice, an activist organization
 * Intellectual Ventures, a privately held intellectual property company
 * InterVarsity Christian Fellowship

Elsewhere

 * Federation of Austrian Industries (Industrievereinigung)
 * Irish Volunteers, a military organization
 * Italia Viva, an Italian centrist political party

Music

 * Subdominant, in music theory

Recordings

 * IV (The Aggrolites album), 2009
 * IV (Angband album), 2020
 * IV (BadBadNotGood album), 2016
 * IV (Black Mountain album), 2016
 * IV (Cypress Hill album), 1998
 * IV (Diamond Rio album), 1996
 * IV (Goatsnake album), 1998
 * IV (Godsmack album), 2006
 * IV (Hiroyuki Sawano album), 2021
 * I.V. (Loma Prieta album), 2012
 * IV (Maylene and the Sons of Disaster album), 2011
 * IV (Ton Steine Scherben album), 1981
 * IV (The Stranglers album), 1980
 * IV (To/Die/For album), 2004
 * IV (Veruca Salt album), 2006
 * IV (Winger album), 2006
 * IV (Željko Joksimović album), 2005
 * Faust IV, 1973
 * Good Apollo, I'm Burning Star IV, Volume One: From Fear Through the Eyes of Madness, by Coheed and Cambria, 2005
 * Led Zeppelin IV, 1971
 * Toto IV, 1982
 * IV (EP), a 2013 EP by The 1975
 * "I.V." (song), by X Japan, 2008
 * IV, 1998 album by Siam Shade
 * IV, a 1990 EP by The Lookouts

Places

 * Ivory Coast, a country in West Africa
 * IV postcode area, north Scotland
 * Isla Vista, California, United States

In science, technology and mathematics

 * Intravenous therapy, a route of administration of a drug
 * I–V curve, current–voltage curve characteristic
 * Implied volatility, a term in financial mathematics
 * Independent variable, in mathematical and statistical modeling
 * Independent verification systems, in voting machines
 * Induction variable, in computer science
 * Initialization vector, in cryptography
 * Instrumental variable, in statistics
 * Intrinsic viscosity
 * Trochlear nerve, the fourth cranial nerve

Other uses

 * 4 (number) in Roman numerals
 * Four-Phase Systems, a computer company whose logo was a stylized "IV"
 * International Viewpoint, an online magazine of the Trotskyist reunified Fourth International
 * Inter vivos trust, a legal instrument
 * Coleman Williams, American country music singer known professionally as IV