Cooee! (IPA /ku:'i:/) is a shout used in Australia, usually in the Bush, to attract attention, find missing people, or indicate one's own location. When done correctly - loudly and shrilly - a call of "cooee" can carry over a considerable distance. It is also known a a call of help which can blend in with different natural sounds in the bush.

The word "cooee" originates from the Dharuk language of the original inhabitants of the Sydney area. It means "come here", and has now become widely used in Australia as a call over distances. It was known among white settlers in colonial times and Watkin Tench refers to the Aborigines of Sydney calling to each other in this way.

One of Sir Arthur Conan Doyle's Sherlock Holmes mysteries hinges on the use of "cooee!". "The Boscombe Valley Mystery" is solved partly because, unlike everyone else, Holmes recognizes the call is commonly used among Australians.

An expression "within cooee of" has developed. It means "within a manageable distance", and seems to be confined to New Zealand and Australian English, and is almost exclusively used in the negative sense (i.e. "you're not even within cooee", meaning not close to) and in the abstract (e.g. "How much do you think they spent redoing this place?" "Oh, I don't know, $5000?". "You're not even within cooee - 25,000!"

The word cooee has become a name of many organisations, places and even events. Perhaps the most historic of these was the Cooee March during the First World War. It was staged by 35 men from Gilgandra, New South Wales, 766 km northwest of Sydney, as a recruiting drive after enthusiasm for the war waned in 1915 with the first casualty lists. The men marched to Sydney calling "Cooee!" to encourage others to come and enlist. When they reached Sydney on 12 December, the group had grown to 277 men. To this day, Gilgandra holds a yearly Cooee Festival in October to commemorate the event. Other Cooee Festivals occur across Australia. Cooee is also the name of a suburb in the Tasmanian city of Burnie.

Richard White indicates the important means of demonstrating Australian nationality with the call taking on a consciously nationalistic meaning. He also documents its spread through the Empire, to New Zealand and South Africa.