John Obadiah Westwood (22 December 1805 – 2 January 1893) was an English entomologist and archaeologist also noted for his artistic talents.

In his spare time he studied Anglo-Saxon and medieval manuscripts and earned a living by illustrating and writing.

[3] Among the prominent writers and naturalists he associated with was James Rennie, whom he assisted in the editing of Gilbert White's The Natural History and Antiquities of Selborne in 1833.

[5] Although he worked on insect classification and diversity for more than thirty years from the publication of Darwin's Origin of Species, he never accepted ideas on evolution.

[7] Westwood was among the first to attempt an estimate of the total number of species of insects which he put at half a million.

[8] In 1839, Westwood married Eliza Richardson (d. 1882), who accompanied him on all his archæological tours, and who assisted in making sketches and rubbings of the inscribed stones for his 'Lapidarium Walliæ.'

He received the Royal Society's medal, based on recommendations from many including Darwin, in 1855 for his work on insects.

On 30 December 1892, not long after returning home from a convention in London, Westwood had suddenly collapsed of a cerebral haemorrhage, which left him hospitalised.