YD, or Yd may refer to:

• Yard (yd), a unit of length
• Nissan YD engine, an automobile engine
• Yarmouth–Dennis Red Sox, or Y-D Red Sox, a collegiate summer baseball team based in South Yarmouth, Massachusetts
• Younger Dryas, a geological period from c. 12,900 to c. 11,700 calendar years ago
• South Yemen (ISO 3166-1 code YD)
• A US Navy hull classification symbol: Floating derrick (YD)
• YD - Young Diem / Early Day
• Yd. (retailer), an Australia and New Zealand clothing retail chain