The Hunslet Austerity 0-6-0ST is a class of steam locomotive designed by Hunslet Engine Company for shunting. The class became the standard British shunting locomotive during the Second World War, and production continued until 1964 at various locomotive manufacturers.

At the outbreak of the Second World War, the WD had initially chosen the LMS 'Jinty' 3F 0-6-0T as its standard shunting locomotive but was persuaded by Hunslet that a simplified version of their more modern 50550 design would be more suitable. The first locomotive was completed at their Leeds works at the start of 1943.

Hunslet subcontracted some of the construction to Andrew Barclay Sons & Co., W. G. Bagnall, Hudswell Clarke, Robert Stephenson and Hawthorns and the Vulcan Foundry in order to meet delivery requirements. After D-Day, they were used on Continental Europe and in North Africa, as well as at docks and military sites in Britain.

A total of 377 had been built for the WD by 1947 When the end of the war reduced the need for locomotives, the military started to review its fleet:  90 locomotives were kept by the military for use on their railways, 75 locomotives were sold to the LNER and classified as J94, 27 that had been loaned to Nederlandse Spoorwegen were sold to that company in 1947, becoming the NS 8800 class, 11 were loaned to the Nederlandsche Staatsmijnen, who bought 9 of them. Others were sold for industrial use.

As the final WD locomotives were being delivered, the NCB was placing orders for identical locomotives to be used at their collieries. Between 1948 and 1964, 77 new "Austerity" locomotives were built for the NCB. A further fourteen engines were ordered in 1952 by the British Army to supplement its 90 existing engines. The Yorkshire Engine Company also built eight locomotives to this design in 1954 for use in ironstone quarries and at Scunthorpe Steelworks.

70 Austerities have been preserved on heritage railways, many in working order. Several have been painted as LNER Class J94s to represent mainline rather than industrial use.