Osmond Gilles (24 August 1788 – 25 September 1866) was a settler, pastoralist, mine owner and South Australia’s first colonial treasurer.
Born in London, in 1816 he went into partnership with Philip Oakden in Hamburg, Germany as a merchant, where in 1825 he married Patience Oakden, his partner's sister. Returning to England, his wife died in 1833, leaving Gilles widowed and childless. Although he never remarried he took on several protegees, including his nephew John Oakden.
Gilles migrated to the new Australian colony on the HMS Buffalo in 1836 and acted as the Colonial Treasurer. He was a prominent businessman and land owner, with the largest holdings of any settler in 1837, and sat on the Street Naming Committee on 23 May, 1837.
He is remembered by Gilles Street in the Adelaide Central Business District, Glen Osmond Road, OG Road and the Adelaide suburbs of Glen Osmond and Gilles Plains. A new suburb formed from a portion of Gilles Plains has been named Oakden after Gilles' wife.