Septimus Denbigh Alldis (5 February 1886 – 22 July 1929) was an Australian politician.
A schoolteacher, he taught in Orange from 1901 and also studied at the University of Sydney, receiving his Bachelor of Arts in 1922.
In 1925 he was elected to the New South Wales Legislative Assembly as a Labor member for Eastern Suburbs.
He returned to teaching, primarily classics, after his defeat and wrote several Latin textbooks.
This article about an Australian Labor Party member of the Parliament of New South Wales is a stub.