The Niger-class frigates were 32-gun sailing frigates of the fifth rate produced for the Royal Navy. They were designed in 1757 by Sir Thomas Slade, and were an improvement on his 1756 design for the 32-gun Southampton-class frigates. Slade's design was approved in September 1757, on which date four ships were approved to be built to these plans - three by contract and a fourth in a royal dockyard.