In linguistics, a determiner phrase (DP) is a syntactic category, a phrase headed by a determiner. In English and many other languages, determiner phrases have a noun phrase as a complement. This is opposed to the alternative view that determiners are specifiers of the noun phrase. The overwhelming majority of transformational grammarians today adopt the DP hypothesis in some form or other. However, large numbers of both traditional and formal grammarians consider nouns, not determiners, to be the heads of NPs.
Determiners govern the referential or quantificational properties of the noun phrases they embed. The idea that noun phrases preceded by determiners are determiner phrases is known as the DP hypothesis. The DP hypothesis goes very well with the theory of generalized quantifiers, which is the prevailing theory of the semantics of determiners.