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
Businesses and organizations
- IBC Airways (IATA airline designator II)
Music
- Supertonic, in music
Albums
- II (2 Unlimited album), 1998
- II (Bad Books album), 2012
- II (Boyz II Men album), 1994
- II (Capital Kings album), 2015
- II (Charade album), 2004
- 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 (Krux album), 2006
- II (Kurious album), 2009
- II (Lords of Black album), 2016
- II (Maylene and the Sons of Disaster album), 2007
- II (METZ album), 2015
- II (Moderat album), 2013
- II (Sahg album), 2008
- II (Seven Thorns album), 2013
- II (The Common Linnets album), 2015
- II (The Kinleys album), 2000
- II (The Presidents of the United States of America album), 1996
- II (Unknown Mortal Orchestra album), 2013
- II (Xerath album), 2011
- Crystal Castles II, 2010
- Led Zeppelin II, 1969
- Meat Puppets II, 1984
- Viva Koenji!, Koenji Hyakkei album, also known as 弐(II)
Songs
- ii (2018) by CHVRCHES
People
- 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)
- Institutional Investor (magazine), an American finance magazine
- Income inequality, or the wealth gap, in economics
- Index Islamicus, a bibliography database of publications about Islam and the Muslim world
- Internet Infidels, a discussion forum
- Internationalization Index, used by the UN to rank nations and companies in evaluating their degree of integration with the world economy
- Yi language (ISO 639 alpha-2 code ii)