Nuclear Polynesian refers to those languages comprising the Samoic and the Eastern Polynesian branches of the Polynesian group of Austronesian languages.

The Eastern Polynesian group comprises two major subgroups: Rapa Nui, spoken on Easter Island, and Central Eastern, which is itself comprised of Rapan, and the Marquesic and Tahitic languages.

Nuclear Polynesian is differentiated, among Polynesian languages, by its distinguishing characteristics from the Tongic languages spoken in most of Tonga and in Niue.