Old Gaol Museum, Historical prison museum in Western Australia.

The Old Gaol Museum is a former 1800s prison building that now functions as a museum while keeping its original structure intact. The cells, corridors, and administrative areas hold exhibits with objects, documents, and information about the prison's history.

Plans for the gaol were drawn by Richard Roach Jewell as Public Works Plan PWD No 179, and it was built with convict labour and timber from an old lockup at Bailup. It was finished in 1864 and operational by 1865, serving as a state gaol until 1909. In the 1930s the Dorizzi family lived there, with the sons sleeping in the cells.

The gaol's name comes from Newcastle, the former name of Toodyay. The Moondyne Joe Gallery recounts the escapes of the bushranger held in the timber-lined "native cell", fitted with an iron bar for leg irons. A cell is dedicated to the Dorizzi brothers, who slept there in the 1930s and died as prisoners of war in 1945.

The gaol stands on Clinton Street in Toodyay, with the restored 1891 Police Stable, the 1907 Police Lock-Up and a relocated hundred-year-old shearing shed across the road. The cells and exercise yard are cramped, so allow time to move through the small rooms. The Shire of Toodyay runs the site with a curator and volunteers.

In the 1930s the Dorizzi family lived in the gaol and the sons slept in the cells; three brothers died as prisoners of war in 1945, and one cell is dedicated to them and to local servicemen and women who did not return.