Janet Marion Clarke (née Snodgrass; 4 June 1851 – 28 April 1909) was an Australian socialite and philanthropist.

Janet Marion Snodgrass was born at Doogalloook, a station on the Goulburn River near Yea, Victoria.

In 1873, aged 21, Janet married William Clarke, 41-year-old widower for whom she had previously worked as a governess.

He became the largest landowner in the country, and an exceedingly generous philanthropist, for which in 1882 he was raised to the baronetage (the first Australian to be so honoured).

The couple were known for their lavish hospitality, hosting frequent balls, luncheons, dinners, and garden parties.

[1] In 1882, Clarke was involved in the creation of the Ashes urn, the trophy awarded to the winner of the Test cricket series between Australia and England.

During their 1882–83 tour of Australia, Ivo Bligh were invited to spend Christmas at Rupertswood – Sir William being the president of the Melbourne Cricket Club.