Casing may refer to:
- Cartridge (firearms), shell enclosing the explosive propellant in ammunition
- Casing (borehole), metal tube used during the drilling of a well
- Casing (molding), decorative molding surrounding door or window openings
- Casing (sausage), thin covering holding the food contents of sausage
- Casing (submarine), platform attached to the upper side of a submersible vehicle
- Casing stone, smooth stone covering for a structure such as those on the Giza Necropolis
- Casing (mycology), top layer of soil used during the fruiting stage in mycological cultivation
- Computer case
- Letter case, typography
- Casing a location, surveying a location to potentially commit a robbery