Seal most commonly refers to:

• Pinniped, a diverse group of semi-aquatic marine mammals, many of which are commonly called seals, particularly:
  • Earless seals or "true seals"
  • Fur seals
• Seal (emblem), an emblem used as a means of authentication; both an impression in paper, wax, clay or other medium, and the device used
• Seal (mechanical), a device which helps prevent leakage, contain pressure, or exclude contamination where two systems join
• Seal (surname), an Indian surname of Hindu Bengalis and Rajputs

Seal may also refer to: