Phyllonorycter klemannella is a moth of the Gracillariidae family. It is known from all of Europe, except Greece. The wingspan is 7.5-9.5 mm. The larvae feed on Alnus glutinosa and Alnus incana. They mine the leaves of their host plant. They create a lower-surface tentiform mine between two side veins, often quite far from the midrib. There are many weak folds. There may be several mines in a single leaf. Pupation takes place in a white cocoon within the mine. The cocoon is attached to the roof of the mine and is free from frass, which is concentrated in a corner of the mine, opposite of the cocoon.