Guugu Yimithirr, also rendered Guugu Yimidhirr, Guguyimidjir, and many other spellings, is an Australian Aboriginal language, the traditional language of the Guugu Yimithirr people of Far North Queensland. It belongs to the Pama-Nyungan language family. Most of the speakers today live at the community of Hope Vale, about 46 kilometres (29 mi) from Cooktown. However, as of June 2020 only about half of the Guugu Yimithirr nation speak the language. As such, efforts are being made to teach it to children. Guugu Yimithirr is the source language of the word kangaroo.

The Guugu Yimithirr, also spelt Gugu Yimithirr and also known as Kokoimudji, are an Aboriginal Australian people of Far North Queensland, many of whom today live at Hopevale, which is the administrative centre of Hopevale Shire. At the 2011 census, Hopevale had a population of 1,005 people. It is about 46 kilometres (29 mi) from Cooktown by road. It is also the name of their language. They were both a coastal and inland people, the former clans referring to themselves as a "saltwater people".