Langdon may refer to:

• Several people:
  • John Langdon, 19th century American politician
  • Robert Langdon, a fictional character created by author Dan Brown
  • Samuel Langdon, 18th century American Congregational church clergyman
  • Steven Langdon, Canadian politician
  • Harry Langdon , American silent-movie actor
  • Mary Langdon, American children's author

• Several place names:
  • in the United States:
    • Langdon, North Dakota
    • Langdon, Kansas
    • Langdon, New Hampshire
  • in the United Kingdom:
    • Langdon, Cornwall
    • Langdon, Devon
    • Langdon, Kent
    • Langdon, Pembrokeshire
    • East Langdon, Kent
    • West Langdon, Kent