William Ferguson (c. 1809 – 3 December 1892) was a pioneer settler of South Australia, one of the last surviving emigrants on the HMS Buffalo in 1836.
Ferguson was a farmer born in Hawick, Scotland, and emigrated in 1836 on what has been termed the "First Fleet of South Australia" on Governor Hindmarsh's flagship Buffalo. His wife, who was pregnant when they embarked, gave birth to their first child on board the Buffalo in South Australian waters.
Ferguson was present at the Proclamation ceremony by the Old Gum Tree on 28 December 1836, and helped thatch the roof of the original Government House.
Ferguson purchased two "city acres" in a block stretching between Hindley and Currie Streets, the eastern boundary of which later became a thoroughfare, named Rosina Street after Mrs. Ferguson. He also purchased an acre on Rundle Street where Adelaide Arcade now stands, and another, on which the Primrose Brewery later stood. He also owned property at Magill (or Makgill as it was once spelled). It was there he grew one of the colony's first wheat crops, before selling it to Dr. C. R. Penfold. He also purchased a 248 acres (100 ha) part of section 251, Hundred of Adelaide, which he named "Roseville", again for his wife, and they lived there for around ten years. "Roseville" became the suburb Highgate.
Ferguson later purchased Section 267 at Glen Osmond. This property was first owned by Capt. Berkeley, who sold it to William Sanders, who built a house and named it "Myrtle Bank", then sold to Capt. William Elder, brother of Sir Thomas Elder. Ferguson purchased the property from Elder in 1848 and lived there until he died. That property is now the suburb Myrtle Bank.