Gaagudju (also spelt Gagadu, Gaguju, and Kakadu) is an extinct Australian Aboriginal language formerly spoken in the environs of Kakadu National Park, in Arnhem Land, Northern Territory, Australia.

Explorer Baldwin Spencer incorrectly ascribed the name "Kakadu tribe" to all of the people living in the Alligator Rivers area,[3][4] but Gaagudju was confined to the plains South and East Alligator Rivers.

[2] The language is classed as extinct, since its last fluent speaker, Big Bill Neidjie, died on 23 May 2002;[5][6] Gaagudju has traditionally been classified with the Gunwinyguan languages.

However, in 1997 Nicholas Evans proposed an Arnhem Land family that includes Gaagudju.

Capell (1942) lists the following basic vocabulary items:[7]