Old State Library Building, Brisbane, Neoclassical heritage building in William Street, Brisbane, Australia.

The Old State Library Building is a neoclassical structure featuring a sandstone facade with double-height columns topped by lotus leaf capitals. A distinctive glass mosaic mural adorns its western wall, adding artistic detail to the architectural composition.

This building was completed in 1879 under architect F.D.G. Stanley and originally housed the Queensland Museum. It transitioned to become the State Library in 1902, serving that purpose until 1988.

The building is not open to visitors; it has served as library storage since the State Library moved to South Bank in 1988. Its name recalls the John Oxley Library, founded in 1926 as the main centre for research material on Queensland history and housed here from 1931. The 1959 extension was opened by Princess Alexandra.

The building stands at 159 William Street, between the street and the Brisbane River, overlooking Queens Gardens and next to the North Quay porphyry wall. It is not open to visitors: since the State Library moved to South Bank in 1988 it has been used for library storage. The 1959 mural and sculpture can be seen from outside.

An aluminum sculpture titled 'Enlightenment' stands on the riverside side of the building, depicting three figures reaching toward the sun. This modern artwork creates an interesting contrast with the classical architecture surrounding it.