The letter combination IJ
- the ligature of the letters I and J. In Dutch it usually represents the diphthong [eɪ] or [ɛɪ], and is sometimes considered be to be a single letter: see IJ (digraph).
When used to represent this digraph, IJ can stand for:
- IJ (bay), a body of water near Amsterdam, Netherlands
As an abbreviation, IJ can stand for:
As a code, IJ can be: