Lye is the name of different things:

• Lye is a caustic solution used for glass and soap making. It may have in it:
  • sodium hydroxide (soda lye) or
  • less commonly, potassium hydroxide (potash lye).
• Lye, West Midlands is the name of a small town in England, between Dudley and Stourbridge in the Black Country, Dudley Metropolitan Borough, West Midlands (it was in Worcestershire).
• Lye is a commune of the Indre département, in France.