William Sharp Macleay or McLeay FLS (21 July 1792 – 26 January 1865) was a British civil servant and entomologist.

After graduating, he worked for the British embassy in Paris, following his interest in natural history and at the same time, publishing essays on insects and corresponding with Charles Darwin.

Retiring from this work, he emigrated to Australia, where he continued to collect insects and studied marine natural history.

The first part of Horae Entomologicae included a re-examination of Linnaeus' genus Scarabaeus (12th edition of Systema Naturae, 1767) within the taxonomic context of Pierre Andre Latreille's "Lamellicornes" becoming the first monographer of what today is the family Scarabaeidae.

He also published Annulosa Javanica or an Attempt to illustrate the Natural Affinities and Analogies of the Insects collected in Java by T. Horsfield, no.

Other minor publications on insects include Remarks on the devastation occasioned by Hylobius abietis in fir plantations in the Zoological Journal and several notes in the Transactions of the Entomological Society of London.

This was an attempt to classify animals into related groups and was put forward in Part 2 of his book Horae Entomologicae (1821).