Duncan Malcolm Smith (29 October 1890 – 15 December 1973) was an Australian politician.
He was born in Newcastle to master mariner Duncan Smith and Ada Genge.
On 26 September 1914 he married Marcella Gertrude Smyth, with whom he had four children.
He was expelled from the party in 1926 after failing to vote for the abolition of the Legislative Council, and in the 1930s became associated with Federal Labor.
From 1936 to 1954 Smith was inspector for the Albury school district.