Seahorse (fish) refers to a marine fish belonging to the genus Hippocampus.

Seahorse may also refer to:

• Seahorse (software), a GPG front-end application for GNOME
• a hippopotamus, which was often called a seahorse in the mid-19th century
• The Seahorses, a British rock band
• The Sea Horse, a 1974 off-Broadway play by Edward J. Moore
• USS Seahorse, various United States Navy ships
• , the name of ten Royal Navy ships

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