Sir James Penn Boucaut, KCMG, (29 October 1831 – 1 February 1916) was a South Australian politician and judge. He was a member of the South Australian House of Assembly on four occasions: from 1861 to 1862 for City of Adelaide, from 1865 to 1870 for West Adelaide (1865–1868) and The Burra (1868–1870), from 1871 to 1878 for West Torrens (1871–1875) and Encounter Bay (1875–1878), and a final stint in Encounter Bay in 1878.

At 34 years and 150 days of age, Boucaut was the youngest person to have been appointed Premier of South Australia. He was Premier three times: from 1866 to 1867, from 1875 to 1876, and from 1877 to 1878. He was Attorney-General of South Australia under Premiers John Hart and Henry Ayers, and served variously as Attorney-General, Treasurer, Commissioner of Public Works and Commissioner of Crown Lands and Immigration in his own ministries. He left politics in 1878 when he was appointed a judge of the Supreme Court of South Australia, serving until his retirement in 1905.