William Henry Cavendish-Scott-Bentinck, 4th Duke of Portland, PC (24 June 1768 – 27 March 1854), styled Marquess of Titchfield until 1809, was a British politician who served in various positions in the governments of George Canning and Lord Goderich.

[1] The third Duke, who spared no expense for his heir, sent him to The Hague in 1786 for experience working with the crown's envoy, Sir James Harris.

He remained out of office until April 1827 when he was appointed Lord Privy Seal by his brother-in-law George Canning.

Portland married Henrietta, eldest daughter and heiress of Major-General John Scott of Fife and his wife Margaret (née Dundas), in London on 4 August 1795.

[1] Nearly 10 years later, Portland died at the family seat of Welbeck Abbey, Nottinghamshire, in March 1854, aged 85.