Caloptilia elongella (commonly known as pale red slender) is a moth of the family Gracillariidae. It is known from all of Europe east to eastern Russia. It is also found in North America from British Columbia, south to California and east in the north to New Hampshire and New York. There are two generations per year, with adults on wing in June and again during September, after which they hibernate and reappear in spring. The larvae feed on Alnus glutinosa, Alnus incana and . They mine the leaves of their host plant.