2I

2I or 2-I may refer to:


 * Kosmos-2I Soviet rocket
 * AceKard 2i, one of the Nintendo DS storage devices
 * Base 2i, or Quater-imaginary base
 * The binary icosahedral group 2I
 * SSH 2I (WA), now U.S. Route 97 in Washington
 * The 2i's Coffee Bar in London
 * Polikarpov 2I-N1, alternate name for the Polikarpov DI-1 fighter
 * Kosmos-2I 63S; see List of Kosmos satellites (1–250)
 * 2I/Borisov, the first known interstellar comet