William Lionel Russell Clarke (31 March 1876 – 14 May 1954) was an Australian politician.
He was born in South Yarra to grazier William John Clarke (later a baronet) and Janet Marion Snodgrass.
On 23 September 1908 he married Florence Douglas Mackenzie, with whom he had three children.
In 1910 he purchased the Rupertswood estate from his brother Sir Rupert Clarke; he sold the Ballarat property in 1912 and Rupertswood in 1922, and farmed near Albury from 1912 to 1919 and at Hume Weir from 1919 to 1922.
In 1910 he won a by-election for the Victorian Legislative Council's Southern Province.