The Unicorn class were a class of two 24-gun sixth-rate frigates of the Royal Navy. They served during the War of the Austrian Succession and the Seven Years' War.
They were built to the draught of a French privateer named Le Tygre, which had been captured earlier in 1747. They were initially rated as 24-gun ships, in spite of having four 3-pdr guns mounted on the quarterdeck, as well as the twenty-four 9-pdr guns forming their primary battery on the upper deck. However, in 1756 they were re-classed as 28-gun ships. They are normally seen as the first true sailing frigates to be built for the Royal Navy.