YY

YY may refer to:

  • YY, the call sign prefix for radio stations in Venezuela
  • Peptide YY 3-36, a peptide secreted by the gut in response to a meal, and reduces appetite
  • YY (social network), a major Chinese social network
  • Yy (digraph), digraph used in various Latin alphabets
  • Yy (musician), Canadian musician
  • IATA code for all airlines in a booking, (Used to avoid duplicating requests to individual airlines).