The Institute of Croatian Language and Linguistics (IHJJ) is a public scientific institute. It is the central national scientific research institution for the study of the Croatian language and general linguistics.
The core activities and the mission of the Institute are scientific research in the humanities, specifically in the field of philology. These activities include the systematic scientific study of the Croatian language (its standard language expression, history, dialects and heritage, and the nominal design of basic lexicographic works and other linguistic manuals of the Croatian language) and linguistics.

The Institute is best known and recognized for its work within national monolingual modern and historical lexicography.
The biggest Croatian lexicographic project On-line Croatian Dictionary (MREŽNIK) is currently ongoing and is funded by the Croatian Science Foundation as well as several other capital lexicographic projects such as Etymological dictionary, Old Croatian Dictionary, and historical Kajkawian dictionary.
In addition to this, smaller scale lexicographic projects are also conducted (specialized orthographic, terminological, and dialectological dictionaries etc.). A large number of online linguistic resources is available on the Institute: the Croatian Language Corpus, Language Advice, STRUNA (database of Croatian professional terminology), Croatian Orthography Handbook, diachronic corpus of the Croatian language, a valency database, a database of collocations, a database of Croatian conceptual and linguistic metaphors, idioms database, a database of personal names, etc.