Edward Wesley Janson (14 March 1822 – 14 September 1891) was an English entomologist who specialised in beetles.

A keen entomologist, Janson was elected a Fellow of the Entomological Society of London in 1843.

In 1852, he started a natural history business, Janson & Sons, selling books and specimens.

Janson also assembled a collection of world click beetles (Elateridae), consisting of 25,000 specimens of which 1000 were original types.

The Janson company archive is conserved in the Natural History Museum in London.