Alfred Charles William Harmsworth, 1st Viscount Northcliffe (July 15, 1865, Dublin - August 14, 1922, London) was an influential and successful newspaper owner.

Harmsworth grew up in poverty and embarked on a career as a free-lance journalist. He rose to editorial positions with various papers before deciding to found his own paper, Answers to Correspondents (soon shortened to Answers), a weekly paper with scraps of various information. His sense of the public taste soon made the paper a modest success, and he was joined by his brother, Harold, whose business acumen further helped the paper. Harmsworth soon established several more inexpensive periodicals.

Harmsworth turned to daily newspapers in 1894 when he purchased the nearly bankrupt London Evening News and turned it into a popular paper with brief news reports, a daily story, and a column for women. In just one year, the circulation grew to over 160,000 copies and returned a huge profit. His next venture was the creation of a series of halfpenny dailies, which culminated in the establishment of the Daily Mail in 1896. Harmsworth focused on keeping the reading public interested in the paper by keeping feature articles short, reporting on political and social gossip, and including material for women and serial stories. The first issue immediately set a new world circulation record when it debuted on May 4, 1896, and it never lost the top spot during Hamsworth's lifetime.

During this period, everything that Harmsworth touched became profitable. He bought another nearly bankrupt paper, the Weekly Dispatch, renamed it the Sunday Dispatch, and made it the best-selling Sunday newspaper in the United Kingdom. In 1903, he founded the Daily Mirror to take advantage of the new genre of picture papers and soon had a hit that nearly rivalled the circulation of the Daily Mail. He saved the Observer in 1905, the same year he was made Baron Northcliffe, and purchased The Times in 1908, turning it into a modern newspaper.

Northcliffe used his papers to influence the course of World War I, first calling attention to a shell shortage in the British army and later pressing for both a Ministry of Munitions and the creation of a war cabinet. He joined a military mission to the United States in 1917 and was created Viscount Northcliffe for his service. In 1918, he served as the government's director of propaganda against the Central Powers. By the end of the war he had such a grip on public opinion that he even tried, unsuccessfully, to influence the composition of David Lloyd George's cabinet. In his final years, he was affected by megalomania that damaged his judgment and led to a breakdown.