The term planer may refer to several types of carpentry tools, woodworking machines or metalworking machine tools.
- Plane (tool), a hand tool used to produce flat surfaces by shaving the surface of the wood
- Thickness planer (North America) or thicknesser (UK and Australia), a woodworking machine for making boards of even thickness
- Planer (metalworking), a metalworking machine-tool having a reciprocating work table and a stationary cutting tool
- Jointer (North America) or planer (UK, Canada, and Australia), a woodworking machine for making flat surfaces and straight edges on boards