A tree chipper or wood chipper is a machine used for reducing wood (generally tree limbs or trunks) into smaller parts, such as wood chips or sawdust. They are often portable, being mounted on wheels on frames suitable for towing behind a truck or van.

Tree chippers are typically made of a hopper with a collar, the chipper mechanism itself, and an optional collection bin for the chips. A tree limb is inserted into the hopper (the collar serving as a partial safety mechanism to keep human body parts away from the chipping blades) and started into the chipping mechanism. The chips exit through a chute and can be directed into a truck-mounted container or onto the ground. Typical output is chips on the order of 1 inch (2.5 cm) to 2 inches (5.1 cm) across in size. The resulting wood chips have various uses such as being spread as a ground cover or being fed into a digester during papermaking.