State Library of South Australia, Public library in North Terrace Cultural Precinct, Adelaide, Australia

The State Library of South Australia is a public library in the North Terrace Cultural Precinct in Adelaide. It occupies three connected buildings that represent different periods of architecture: a modern wing, a Victorian hall with two galleries and wrought iron railings, and an older structure from the mid-19th century.

The library's origins lie in the South Australian Literary Association, formed in London on 29 August 1834, whose donated books reached the colony aboard the Tam O'Shanter in December 1836. The South Australian Institute was incorporated in 1855, and its Institute Building opened in 1861. In 1884 the Institute became a statutory body and the first purpose-built library, now the Mortlock Chamber designed by E. J. Woods, opened. The Bastyan Wing followed in 1967 and the glass-foyered Spence Wing in 2003.

The Spence Wing, opened in 2003, is named after Catherine Helen Spence, the 19th-century Adelaide writer and social reformer. It links the Bastyan Wing to the Mortlock Wing. The library holds the Bradman Collection of cricketing memorabilia and the Mountford-Sheard Collection, inscribed on UNESCO's Memory of the World register.

Those planning to do research should check ahead for opening times, as individual rooms and collections are accessible at different hours. The main entrance is on North Terrace and leads directly into the modern section, while the historical wings are reached from inside.

The Mortlock Wing, opened in 1884 and designed by colonial architect E. J. Woods, was built in French Renaissance style with a mansard roof; its two galleries are lit by a glass-domed roof. In August 2014 the U.S. magazine Travel + Leisure placed it among the top 20 most beautiful libraries in the world.