Girdling, also called ring-barking, is the circumferential removal or injury of the bark (consisting of the periderm, phloem, vascular cambium and sometimes also the xylem) of a branch or trunk of a woody plant. Girdling prevents the tree from sending nutrients from its foliage to its roots, resulting in the death of the tree over time, and it can also prevent flow of nutrients in the other direction depending on how much of the xylem is removed. A branch completely girdled will fail; and, when the main trunk of a tree is girdled, the entire tree will die if it cannot regrow from above to bridge the wound. Human practices of girdling include forestry, horticulture, and vandalism. Foresters use the practice of girdling to thin forests. Extensive cankers caused by certain fungi, bacteria or viruses can girdle a trunk or limb. Animals such as rodents will girdle trees by feeding on outer bark, often during winter under snow. Girdling can also be caused by herbivorous mammals feeding on plant bark and by birds and insects, both of which can effectively girdle a tree by boring rows of adjacent holes.

Orchardists use girdling as a cultural technique to yield larger fruit or to set fruit. In viticulture (grape cultivation), the technique is also called "cincturing".