An op-ed, short for "opposite the editorial page", is a type of written prose commonly found in newspapers, magazines, and online publications. They usually represent a writer's strong and focused opinion on an issue of relevance to a targeted audience. Typically ranging from 500 to 700 words, op-eds are distinct from articles written by the publication's editorial board and often feature the opinions of outside contributors. Op-eds allow authors, not part of the publication's editorial team, to express opinions, perspectives, and arguments on various issues of public interest. Unlike traditional editorials, which reflect the opinion of the publication itself, op-eds offer independent voices a foundation to influence public discourse. The New York Times is widely credited with popularizing the modern op-ed format.

The "Page Op.", created in 1921 by Herbert Bayard Swope of The New York Evening World, is a possible precursor to the modern op-ed. When Swope took over as main editor in 1920, he opted to designate a page from editorial staff as "a catchall for book reviews, society boilerplate, and obituaries". Swope explained:

"It occurred to me that nothing is more interesting than opinion when opinion is interesting, so I devised a method of cleaning off the page opposite the editorial, which became the most important in America ... and thereon I decided to print opinions, ignoring facts."

The modern op-ed page was formally developed in 1970 under the direction of The New York Times editor John B. Oakes. Media scholar Michael J. Socolow writes of Oakes' innovation:  

"The Times' effort synthesized various antecedents and editorial visions. Journalistic innovation is usually complex and typically involves multiple external factors. The Times op-ed page appeared in an era of democratizing cultural and political discourse and economic distress for the company itself."

The newspaper's executives developed a place for outside contributors, with space reserved for sale at a premium rate for additional commentaries and other purposes.

The Washington Post too published its own version of the op-ed right before The New York Times debuted in September 1970. Significant differences between The Post's op-ed page and The Times's op-ed page include The Washington Post having no ads and no artistic component. In the 1930s, The Washington Post began referring to its commentary section as the "op-ed page", situated opposite its editorial page. The Los Angeles Times followed suit with a similar designation in the 1950s and 1960s, while The Chicago Tribune had tried a variation of this format as early as 1912. That is to say that while we credit Oakes as the creator of the op-ed, the true origins of the op-ed are highly debated in the journalistic sphere.

With the development and availability of radio and television broadcasting as major information outlets, stakeholders and print journalism workers sought to increase or maintain their audience and relevance. Major newspapers such as The New York Times and The Washington Post began including more opinionated journalism, adding more columns, and increasing the extent of their opinion pages to drive public participation and readership.