Was a United States-based subsidiary label of Atlantic Records (the name Atco is simply an abbreviation of ATlantic COrporation).

Started by Herb Abramson in 1955, it was initially used as an outlet for artists and groups who didn't fit with its parent label - until 1968, Atco was Atlantic's 'pop/rock' label (Atlantic itself being strictly blues, jazz, and R&B/soul) as well as home to almost all of the company's non-African American artists (the main exception being the Young Rascals who were considered a blue-eyed soul group).

In 1991, Atlantic merged Atco with its fledgling label EastWest Records and briefly operated as Atco/Eastwest Records. The following year, the Atco name was dropped and the label continued operating as EastWest Records. In the time since, Atco has stopped releasing new records and its name and logo are only on reissues of its old material.