This chapter describes the major features of the Northwest Caucasian (Abkhaz-Adyghe) language family, comprising Abkhaz, Abaza, West Circassian (Adyghe), East Circassian (Kabardian), and the now extinct Ubykh. Starting with the sociolinguistic setting of the Northwest Caucasian varieties and the history of linguistic research on them, the discussion then proceeds to a description of the most important features of their phonology, morphology, and syntax, concluding with a brief discussion of a number of typologically outstanding features. The chapter, based both on published sources and the authors’ fieldwork data, covers issues such as exuberant consonantism, lexical category underspecification, polysynthetic morphology, expression of spatial meanings in the verb, rich systems of tense, aspect and mood categories, finite and non-finite verbal forms, non-trivial noun phrase syntax, relativization, and complexities of clause-combining. Besides describing the features common for all the languages of the family, we focus on important points of variation among the Northwest Caucasian languages and their dialects, aiming at an adequate representation of the wealth of phenomena they present and highlighting the challenges they offer for typology and linguistic theory.