John Henry de Villiers, 1st Baron de Villiers Kt KCMG PC (15 June 1842 – 2 September 1914) was a Cape lawyer and judge. He was Attorney-General in the Molteno Government, Chief Justice for the Cape Colony, and later the first Chief Justice for the Union of South Africa. As the country's most senior judge for 40 of its formative years, De Villiers is often considered the most influential judge in South African history.