The damson () or damson plum (Prunus domestica subsp. insititia, or sometimes Prunus insititia), also archaically called the "damascene", is an edible drupaceous fruit, a subspecies of the plum tree. Varieties of insititia are found across Europe, but the name damson is derived from and most commonly applied to forms that are native to Great Britain. Damsons are relatively small ovoid plum-like fruit with a distinctive, somewhat astringent taste, and are widely used for culinary purposes, particularly in fruit preserves and jams.

In South and Southeast Asia, the term damson plum sometimes refers to jamblang, the fruit from a tree in the family Myrtaceae. The name "mountain damson" or "bitter damson" was also formerly applied in Jamaica to the tree Simarouba amara.