II

II is the Roman numeral for 2.

II may also refer to:

Biology and medicine

 * Image intensifier, medical imaging equipment
 * Invariant chain, a polypeptide involved in the formation and transport of MHC class II protein
 * Optic nerve, the second cranial nerve

Economics

 * Income inequality, or the wealth gap, in economics
 * Internationalization Index, used by the UN to rank nations and companies in evaluating their degree of integration with the world economy
 * Institutional Investor (magazine), an American finance magazine

Music

 * Supertonic, in music
 * ii, a 2018 song by CHVRCHES

Albums

 * II (2 Unlimited album), 1998
 * II (Aquilo album), 2018
 * II (Bad Books album), 2012
 * II (Boyz II Men album), 1994
 * II (Capital Kings album), 2015
 * II (Charade album), 2004
 * II (The Common Linnets album), 2015
 * II (Compact Disco album), 2011
 * II (Cursed album), 2005
 * II (Darna album), 2003
 * II (Espers album), 2006
 * II (Fuzz album), 2015
 * II (Hardline album), 2002
 * II (High Rise album), 1986
 * II (Khun Narin album), 2016
 * II (Kingston Wall album), 1993
 * II (The Kinleys album), 2000
 * II (Kurious album), 2009
 * II (Last in Line album), 2019
 * II (Lords of Black album), 2016
 * II (Maylene and the Sons of Disaster album), 2007
 * II (METZ album), 2015
 * II (Moderat album), 2013
 * II (The Presidents of the United States of America album), 1996
 * II (Sahg album), 2008
 * II (Seven Thorns album), 2013
 * II (Unknown Mortal Orchestra album), 2013
 * II (Xerath album), 2011
 * II, by Krux, 2006
 * II, by Majical Cloudz, 2011
 * II, by Viva Brother, 2017
 * II, an EP by TNGHT, 2019
 * Crystal Castles II, 2010
 * Led Zeppelin II, 1969
 * Meat Puppets II, 1984
 * Soul Assassins II, 2000
 * Viva Koenji!, Koenji Hyakkei album, also known as 弐(II)
 * Iris II, by Iris, 1987

People and social groups

 * Ii is a Japanese surname, daimyō of Hikone:
 * Ii clan, Japanese clan (Sengoku period)
 * Ii Naomasa, one of four Guardians of the Tokugawa clan
 * Ii Naotora, female daimyō and foster mother of Naomasa
 * Ii Naoyuki, a Japanese author
 * John Papa ʻĪʻī, a Hawaiian noble

Other uses

 * ii (digraph), a digraph in certain romanized alphabets
 * ii (IRC client), short for IRC It, an Internet Relay Chat client for Unix-like operating systems
 * Ii, Finland, a municipality of Finland
 * Illegal immigrant (especially in Hong Kong vernacular)
 * Index Islamicus, a bibliography database of publications about Islam and the Muslim world
 * Internet Infidels, a discussion forum
 * IBC Airways (IATA code: II)
 * Yi language (ISO 639-1: ii)