Genesis and development of EFL learner’s dictionaries, innovative methods and features, and influence on dictionaries in other genres. Pioneering examples (NMED, GEW, ISED) featured simple definition, un/countability, verb patterns, collocations, ample examples, pictorial illustrations, IPA, etc., and paved the path for learner’s dictionaries to come; later generations of learner’s dictionaries converged into corpus basis and towards user-friendliness. Innovative and distinctive features include grading of headword importance, transparent grammar indication, signposts/menus for polysemous entries, controlled defining vocabulary, full-sentence definitions, and extensive use of corpora (manifest in frequency-based sense ordering, identification of frequent grammatical and lexical collocations, authentic illustrative examples). Features of English learner’s dictionaries are now incorporated in dictionaries for native speakers, and English learner’s dictionaries and English–Japanese dictionaries have been mutually influential. The evolution and innovation of learner’s dictionaries are mainly motivated by EFL learners’ needs for comprehension and production, driven by users’ rudimentary reference skills, and influenced by digital technology.