Côte d'Ivoire, from the NATO country code

Grand Theft Auto IV, a video game that was referred to simply as IV by the developers before its release

Isla Vista, an unincorporated community in Santa Barbara County, California, US

Intravenous therapy, giving a liquid substances directly into a vein

Irish Volunteers, a historical organisation from Ireland.

IV St. Albert 05-06 (Concepcion Catholic School IV-B section)

Inter vivos trust, a living trust created during a person's lifetime

Instrumental variable, a statistical analysis method

Implied volatility in financial mathematics

InterVarsity Christian Fellowship, a Christian ministry for college students

Initialization vector, a nonsecret binary vector in cryptography

Toto IV, the fourth album of the band Toto

IrfanView, a freeware image viewer

IV (Cypress Hill album), the fourth album of Cypress Hill

IV (Godsmack album), the fourth album of Godsmack

IV (Faust album), also known as Faust IV, the fourth album by Faust

Immigration voice a non-profit organisation working to alleviate problems faced by legal high-skilled foreign workers in the United States.

IV (Winger album), an album of Winger

IV (Veruca Salt album), the fourth album by Veruca Salt

Independent verification systems, voting machines

International Viewpoint, the monthly magazine of the Reunified Fourth International

Current-voltage in electronics where I=current and V=voltage

IV (Diamond Rio album), a 1996 album by Diamond Rio

IV (To/Die/For album), the fourth album of To/Die/For

Industrievereinigung, Federation of Austrian Industry

IV as the Roman number for four may refer to:

Led Zeppelin IV, the fourth album by Led Zeppelin containing the popular song "Stairway to Heaven"

I.V., X Japan song