Leech may refer to:

• Leech, a primitive animal
  • In pre-scientific medicine, leeching was an alternative form of blood letting in which blood would be removed via leeches
• Leech (term), slang term used to refer usually to one who consumes resources without returning anything
• Leech (computing), in computing, someone who uses others' information or effort but does not provide any in return
• The aft edge of a sail
• Leech (comics), a fictional character in the X-Men universe. He is aligned with the Morlocks, and has the ability to leech energy off of anyone he touches
• Leech lattice, in mathematics, a lattice Λ in R²⁴, discovered by John Leech (mathematician)

See also

• Leach

Leechen | Leecher