Exoteleia dodecella (L.) (Lepidoptera: Gelechiidae), a native of Europe, was first documented from North America at several locations in eastern Canada. Additional records indicate this moth has now spread throughout New England and west to northern Pennsylvania, New York, and possibly into Michigan in the United States. A second introduction of E. dodecella has occurred near the Vancouver area of British Columbia in Canada. To help with the identification of E. dodecella, morphological, biological, and molecular evidence are presented. Key features of the adult, larval, and pupal morphology are compared to other species of Exoteleia and illustrated with line drawings or scanning electron micrographs. The high sequence divergence (>7%) of E. dodecella compared to samples of related native North American species demonstrates that DNA barcodes are a useful identification tool for this pest. A summary of the biology of E. dodecella, including 12 species of larval and pupal parasitoids (most representing new host records), is also included.