Gunnedah (/ˈɡʌnədɑː/) is a town in north-central New South Wales, Australia and is the seat of the Gunnedah Shire local government area. In the 2021 census the town recorded a population of 8,338. Gunnedah is situated within the Liverpool Plains, a fertile agricultural region, with 80% of the surrounding shire area devoted to farming. The Namoi River flows west then north-west through the town providing water beneficial to agricultural operations in the area.

The Gunnedah area is a significant producer of cotton, coal, beef, lamb and pork, and cereal and oilseed grains. Gunnedah is also home to AgQuip, Australia's largest annual agricultural field day.

Gunnedah is located on the Oxley and Kamilaroi Highways providing convenient road links to much of the northern sector of the state including to the regional centre Tamworth, 75 kilometres (47 mi) distant. The town has a station on the Mungindi railway line and is served by the daily NSW TrainLink Xplorer passenger service to and from Sydney and Moree.

It claims the title of being the "Koala Capital of World", although recently there have been concerns over the health of the local koala population and the impacts of climate change on koala habitat.

Gunnedah and the surrounding areas were originally inhabited by Aboriginal Australians speaking the Kamilaroi (Gamilaraay) language. The name of the town in Kamilaroi means "Place of White Stones". In 1818, English surveyor general John Oxley traversed the district, for which a monument pays tribute to him at the base of Mullaley Mountain. The area now occupied by the town was settled by European sheep farmers in 1833 or 1834. With settlement in the area focused on wool production, Gunnedah was initially known as 'The Woolshed' until taking its name from the local Indigenous people who called themselves the Gunn-e-darr, the most famous of whom was Cumbo Gunnerah.

Coal was discovered on Black Jack Hill in 1877. By 1891, 6,000 tons of coal had been raised from shafts. The Gunnedah Colliery Company was registered in May 1899 and by 22 June a private railway some 5.7 kilometres (3.5 mi) in length had been completed from the railway station to their mine. In September 1957, the Government Railway took over the working of the line.

Dorothea Mackellar wrote her famous poem My Country (popularly known as I Love a Sunburnt Country) about her family's farm near Gunnedah. This is remembered by the annual Dorothea Mackellar Poetry Awards for school students held in Gunnedah.

In early 2012, Gunnedah experienced a mining boom resulting in rental properties being leased by mining companies for up to $1,350 per week.