A tabloid is a newspaper format characterized by its compact size, smaller than a broadsheet. The term originates from the 19th century, when the London-based pharmaceutical company Burroughs Wellcome & Co. used the term to describe compressed pills, later adopted by newspapers to denote condensed content. There are two main types of tabloid newspaper: red tops and compact, distinguished by editorial style.

Red top tabloids are distinct from broadsheet newspapers, which traditionally cater to more affluent, educated audiences with in-depth reporting and analysis. However, the line between tabloids and broadsheets has blurred in recent decades, as many broadsheet newspapers have adopted tabloid or compact formats to reduce costs and attract readers.

Globally, the tabloid format has been adapted to suit regional preferences and media landscapes. In countries like Germany and Australia, tabloids such as Bild and The Daily Telegraph have significant readerships and political clout.

The word tabloid comes from the name given by the London-based pharmaceutical company Burroughs Wellcome & Co. to the compressed tablets they marketed as "Tabloid" pills in the late 1880s. The word tabloid was soon applied to other small compressed items. A 1902 item in London's Westminster Gazette noted, "The proprietor intends to give in tabloid form all the news printed by other journals." Thus, by 1901, tabloid journalism originally meant condensed stories in a simplified, easily absorbed format. Later, by 1918, tabloid was also being used to refer to smaller sheet newspapers that contained the condensed stories.

Tabloid newspapers, especially in the United Kingdom, vary widely in their target market, political alignment, editorial style, and circulation. Thus, various terms have been coined to describe the subtypes of this versatile paper format. There are, broadly, two main types of tabloid newspaper: red top and compact. The distinction is largely of editorial style; both red top and compact tabloids span the width of the political spectrum from socialism to capitalist conservatism, although red-top tabloids, on account of their historically working-class target market, generally embrace populism to some degree. Red top tabloids are so named due to their tendency, in British and Commonwealth usage, to have their mastheads printed in red ink; the term compact was coined to avoid the connotation of the word tabloid, which implies a red top tabloid, and has lent its name to tabloid journalism, which is journalism after the fashion of red top reporters.

Red top tabloids, named after their distinguishing red mastheads, employ a form of writing known as tabloid journalism; this style emphasizes features such as sensational crime stories, astrology, gossip columns about the personal lives of celebrities and sports stars, and junk food news. Celebrity gossip columns which appear in red top tabloids and focus on their sexual practices, misuse of narcotics, and the private aspects of their lives often border on, and sometimes cross the line of defamation.

Red tops tend to be written with a simplistic, straightforward vocabulary and grammar; their layout usually gives greater prominence to the picture than to the word. The writing style of red top tabloids is often accused of sensationalism and extreme political bias; red tops have been accused of deliberately igniting controversy and selectively reporting on attention-grabbing stories, or those with shock value. In the extreme case, tabloids have been accused of lying or misrepresenting the truth to increase circulation.

Examples of British red top newspapers include The Sun, the Daily Star and the Daily Mirror. Although not using red mastheads, the Daily Mail and Daily Express also use the 'tabloid journalism' model.