Sir Josiah Henry Symon (27 September 1846 – 29 March 1934) was an Australian lawyer and politician.
He was a Senator for South Australia from 1901 to 1913 and Attorney-General of Australia from 1904 to 1905.
Symon was born in Wick, Caithness, Scotland.
He immigrated to South Australia in 1866 and became one of the colony's leading barristers.
He was appointed Attorney-General of South Australia in 1881, serving only a few months, and won election to the Parliament of South Australia in the same year.
Symon supported the federation movement and won election to the Senate at the 1901 federal election.
He served as Attorney-General in the Reid Government (1904–1905).
After his death he donated his extensive personal collection to the State Library of South Australia.