Campbell Drummond Riddell (9 January 1796 – 1858) was an Australian Colonial public servant who served as Colonial Treasurer.
Riddell was the son of Thomas Milles Riddell (d.1796) and Margaretta, née Campbell. He was the grandson of Sir James Riddell Bt who was created first baronet, of Ardnamurchan, Argyllshire, Scotland.
He was educated at Christ Church College, Oxford, but he did not take a degree. Upon joining the Colonial Service he served in Ceylon, where he met and married his wife, and later in Sydney, New South Wales where he served as the Colonial Treasurer.
After retiring from the colonial service he was appointed to the New South Wales Legislative Council. He also served as President of the Australian Club.
He died in England in 1858.