Caisson (French for "box") may refer to:

• Caisson (engineering), a sealed underwater structure
• Caisson (vehicle), a two-wheeled cart for carrying ammunition, also used in certain state and military funerals
• Caisson (Asian architecture), a spider web ceiling
• Caisson (lock gate), a gate for a dock or lock, constructed as a floating caisson
• Caisson (pen name), of Edward Sperling
• Caisson (western architecture), a type of coffer
• Caisson disease, or decompression sickness
• Caisson lock, a type of canal lock

• Caisson foundation
• Kazon, a fictional alien race in Star Trek
• Khe Sanh