Ii or ii can refer to:

• ii (digraph), a digraph in certain romanized alphabets
• Ii, Finland, a municipality of Finland
• Ii is a Japanese surname, daimyo of Hikone:
  • Ii clan, Japanese clan (Sengoku period)
  • Ii Naomasa, one of four Guardians of the Tokugawa clan
  • Ii Naoyuki, a Japanese author
• iiNet, a major Australian Internet service provider trading as simply ii
• 2 (number), in lowercase Roman numerals
• Illegal immigrant (especially in Hong Kong vernacular)
• Invariant chain
• Income inequality, the wealth gap
• ii (IRC client), short for IRC It, an Internet Relay Chat client for Unix-like operating systems
• John Papa ʻĪʻī, Hawaiian noble
• Yi language (ISO 639 alpha-2, ii)
• Supertonic, in music

Year 2 (II) was a common year starting on Sunday or Monday (link will display the full calendar) of the Julian calendar (the sources differ, see leap year error for further information) and a common year starting on Sunday of the proleptic Julian calendar. At the time, it was known as the Year of the Consulship of Vinicius and Varus (or, less frequently, year 755 Ab urbe condita). The denomination 2 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.

2 (Two; ) is a number, numeral, and glyph. It is the natural number following 1 and preceding 3.

II is the Roman numeral for two. This may also refer to:

• II (The Presidents of the United States of America album), 1996
• II (Boyz II Men album), 1994
• II (Crystal Castles album), 2010
• II (2 Unlimited album), 1998
• II (Espers album), 2006
• II (Krux album), 2006
• II (Hardline album), 2002
• Viva Koenji!, Koenji Hyakkei album, also known as 弐(II)
• II (Maylene and the Sons of Disaster album), 2007
• II (Kingston Wall album), 1993
• II (Darna album), 2003
• II (The Kinleys album), 2000
• II (Charade album), 2004
• Led Zeppelin II, 1969
• Meat Puppets II, 1984
• II (Cursed album), 2005
• II (Unknown Mortal Orchestra album), 2013
• II (Moderat album), 2013
• II (Capital Kings album), 2015
• II (METZ album), 2015