The accusative case (abbreviated acc) of a noun is the grammatical case used to mark the direct object of a transitive verb. The same case is used in many languages for the objects of (some or all) prepositions. It is a noun that is having something done to it, usually joined (such as in Latin) with the nominative case, making it an indirect object.

The accusative case existed in Proto-Indo-European and is present in some Indo-European languages (including Latin, Sanskrit, Greek, German, Polish, Swedish, Romanian, Russian, Ukrainian), in the Uralic languages, in Altaic languages, and in Semitic languages (such as Classical Arabic). Finnic languages, such as Finnish and Estonian, have two cases to mark objects, the accusative and the partitive case. In morphosyntactic alignment terms, both perform the accusative function, but the accusative object is telic, while the partitive is not.

Modern English, which almost entirely lacks declension in its nouns, does not have an explicitly marked accusative case even in the pronouns. Such forms as whom, them, and her derive rather from the old Germanic dative forms, of which the -m and -r endings are characteristic. This conflation of the old accusative, dative, instrumental, and (after prepositions) genitive cases is the oblique case. Most modern English grammarians no longer use the Latin accusative/dative model, though they tend to use the terms objective for oblique, subjective for nominative, and possessive for genitive (see Declension in English). Hine, a true accusative masculine third person singular pronoun, is attested in some northern English dialects as late as the 19th century.