William Stephen (1829 – 28 December 1913) was an Irish-born Australian politician.
He was born in County Cavan to farmer James Stephen and Jane Smith. He and his family moved to Australia in 1848, and after unsuccessful attempts at mining in New South Wales and Victoria he settled in Sydney as a gardener and fruitgrower. On 14 April 1857 he married Mary Montgomery, with whom he had seven children. After converting the swamps around Botany Bay into fertile land, he established a business in woolscouring and fellmongering. In 1887 he was elected to the New South Wales Legislative Assembly as the Free Trade member for Redfern. He was defeated in 1891, but returned to the Assembly in 1894 as the member for Botany. Defeated again in 1895, he contested the Assembly again in 1898 and 1901, and in 1901 was elected Mayor of Botany. He died at Botany in 1913.