any member of the fern genus Dryopteris, in the family Dryopteridaceae. The genus has about 250 species with worldwide distribution. Shield ferns are medium-sized woodland plants with bright green, leathery leaves that are several times divided. They have numerous round spore clusters (sori) attached along the veins on the underside of the leaves and protected by a tissue covering (indusium) that is reniform (kidney-shaped).

Members of the closely related genus Polystichum, which differ from Dryopteris mainly in their peltate (umbrella-shaped) leaves, are also commonly known as shield fern. Polystichum contains about 200 species of worldwide distribution.