As the World Turns (often abbreviated as ATWT) is an American television soap opera that aired on CBS for 54 years from April 2, 1956, to September 17, 2010. Irna Phillips created As the World Turns as a sister show to her other soap opera Guiding Light. With 13,763 hours of cumulative narrative, As the World Turns has the longest total running time of any television show. In terms of continuous run of production, As the World Turns at 54 years holds the fourth-longest run of any daytime network soap opera on American television, surpassed only by General Hospital, Guiding Light, and Days of Our Lives. As the World Turns was produced for its first 43 years in Manhattan and in Brooklyn from 2000 until 2010.

Set in the fictional town of Oakdale, Illinois, the show debuted on April 2, 1956, at 1:30 p.m. EST, airing as a 30-minute serial. Prior to that date, all serials had been 15 minutes in length. As the World Turns and The Edge of Night, which premiered on the same day at 4:30 p.m. EST, were the first two to be 30 minutes in length from their premieres. At first, viewers were indifferent to the new half-hour serial, but ratings picked up in its second year, eventually reaching the top spot in the daytime Nielsen ratings by fall 1958. In 1959, the show started a streak of weekly ratings wins that was not interrupted for over 12 years. The show switched to color on August 21, 1967, and expanded from a half hour in length to one hour daily starting on December 1, 1975, when The Edge of Night moved to ABC. In the year-to-date ratings, As the World Turns was the most-watched daytime drama from 1958 until 1978, with some ten million viewers tuning in each day. At its height, core actors such as Helen Wagner, Don MacLaughlin, Don Hastings, and Eileen Fulton became nationally known. Wagner, Hastings, and Fulton are also three of longest serving actors in the history of American soap operas.

The show passed its 10,000th episode on May 12, 1995, and celebrated its 50th anniversary on April 2, 2006. On September 18, 2009, As the World Turns became the last remaining Procter & Gamble-produced soap opera for CBS after Guiding Light aired its final episode on the network.

On December 8, 2009, CBS announced it was canceling As the World Turns after a run of almost 54 years due to low ratings. The show taped its final scenes on June 23, 2010, and its final episode aired on September 17, 2010. Reruns of The Price Is Right, Let's Make a Deal, and The Young and the Restless took over the As the World Turns time slot between September 20 and October 15, 2010, for four weeks. On October 18, 2010, CBS replaced As the World Turns with a new talk show called The Talk.