Thomas Pennant (14 June OS 1726 – 16 December 1798) was a Welsh naturalist, traveller, writer and antiquarian. He was born and lived his whole life at his family estate, Downing Hall near Whitford, Flintshire, in Wales.

As a naturalist he had a great curiosity, observing the geography, geology, plants, animals, birds, reptiles, amphibians and fish around him and recording what he saw and heard about. He wrote acclaimed books including British Zoology, the History of Quadrupeds, Arctic Zoology and Indian Zoology although he never travelled further afield than continental Europe. He knew and maintained correspondence with many of the scientific figures of his day. His books influenced the writings of Samuel Johnson. As an antiquarian, he amassed a considerable collection of art and other works, largely selected for their scientific interest. Many of these works are now housed at the National Library of Wales.

As a traveller he visited Scotland and many other parts of Britain and wrote about them. Many of his travels took him to places that were little known to the British public and the travelogues he produced, accompanied by painted and engraved colour plates, were much appreciated. Each tour started at his home and related in detail the route, the scenery, the habits and activities of the people he met, their customs and superstitions and the wildlife he saw or heard about. He travelled on horseback accompanied by his servant, Moses Griffith, who sketched the things they encountered, later to work these up into illustrations for the books. He was an amiable man with a large circle of friends and was still busily following his interests into his sixties. He enjoyed good health throughout his life and died at Downing at the age of seventy two.