The South Australian Railways 600 class was a class of 4-6-2 steam locomotives operated by the South Australian Railways.

The 600 class were part of an order for 30 steam locomotives[note 1] placed with Armstrong Whitworth, England, in 1924, as part of the rehabilitation of the state's rail system overseen by railways commissioner William Webb.

The 600 class design was based on the USRA Light Pacific, although modifications were made by SAR's Chief Mechanical Engineer, Fred Shea, including those necessary to fit South Australia's tighter loading gauge, which was lower than that of the United States.

They were also fitted with large smoke deflectors over their lifetime.

Ten locomotives of the South Australian Railways 620 class were built at Islington Railway Workshops in 1936–1938, to a similar design.