Perth Gaol, Museum building in Central Perth, Australia

Perth Gaol is a limestone building just west of Beaufort Street, next to the Western Australian Museum. Its cruciform plan held cells, a chapel, gaolers' quarters and prisoners' yards; the central cell block was removed in the 1890s and the roof lowered, then raised again in renovations from 1968 to about 1976.

Designed by Richard Roach Jewell, the gaol was built between 1854 and 1856 with stone cut by convicts at Rocky Bay and floated up the Swan River. It operated until March 1888, when the last prisoner was transferred to Fremantle Prison. In 1891 it became the Geological Museum, and in 1892 the Perth Museum.

The gaol became the Geological Museum in 1891, housing Reverend Charles Nicolay's collection, and was renamed Perth Museum in 1892 with the Swan River Mechanics' Institute collection and Aboriginal artefacts from the Police Department. Since 1899 it has served as a museum annex to the adjacent Jubilee Building.

The gaol stands beside the Western Australian Museum in the Perth Cultural Centre, near the Beaufort and Francis Streets intersection, with the Art Gallery, J S Battye Library and State Library nearby. Renovations from 1968 to about 1976 added fire doors and improved ground and first floor access for visitors. The roof was raised back to its original height, though the interior was not returned to its exact original layout.

The Enquirer newspaper used the hanging of Samuel Stanley and an Aboriginal man named Jacob near the Perth Causeway to argue that part of the new gaol should have a proper execution yard. The first execution there followed in 1855, and after complaints the gallows were enclosed so the public could not watch.