Edward Henry St John QC (pr: Sinj'n) (15 August 1916 – 24 October 1994) was a prominent Australian barrister, anti-nuclear activist and Liberal politician in the 1960s.
His political career came to a controversial end after he criticised the Prime Minister John Gorton.
His book A Time to Speak was an account of his eventful three years in politics from 1966 to 1969.
Justice Michael Kirby described St John as a "contradictory, restless, reforming spirit".