Treen is a generic name for small handmade functional household objects made of wood. Hence treen is distinct from furniture, such as chairs, and cabinetry, such as clocks and cupboards.
Anything from wooden plates and bowls, snuff boxes and needle cases, spoons and staybusks to shoehorns and chopping boards can be classed as treen. Domestic and agricultural wooden tools are also usually classed in with treen.

Before the advent of cheap metal wares in industrialized societies, and later plastic, wood played a much greater part as the raw material for common objects. Turning and carving were the key manufacturing techniques. The selection of wood species was important, and close-grained native hardwoods such as box, beech and sycamore were particularly favoured, with occasional use of exotics, such as lignum vitae for mallet heads.

Wooden objects have survived relatively less well than those of metal or stone, and their study by archaeologists and historians has been somewhat neglected until recently. Their strongly functional and undecorated forms have however been highly regarded by designers and collectors.

The scholarly study of treen was greatly advanced by Edward Pinto (1901-1972), who started collecting in his childhood and wrote a definitive book on the subject. In 1965, when Birmingham Museum & Art Gallery purchased his collection, it contained over 7,000 items.