IYKYK is an abbreviation for 'if you know, you know' often used to describe inside jokes.

IYKYK may also refer to:

IYKYK (If You Know You Know), song by Illit IYKYK, song by Belly IYKYK, song by XG IYKYK, song by Lil Durk IYKYK, song by Dierks Bentley IYKYK (EP), extended play by Omega X