Sesame Street is an American children's television program known for its combination of Jim Henson's The Muppets, animation, short films, humor, and cultural references. It premiered on public broadcasting television stations on November 10, 1969, to positive reviews, some controversy, and high ratings. It was the first preschool educational television program to base its contents and production values on laboratory and formative research, and the first to include a curriculum "detailed or stated in terms of measurable outcomes".

Sesame Street was conceived in 1966 during discussions between television producer Joan Ganz Cooney and Carnegie Foundation vice president Lloyd Morrisett. Their goal was to create a children's television show that would "master the addictive qualities of television and do something good with them", such as helping young children prepare for school. After two years of research, the newly formed Children's Television Workshop (CTW) received a combined grant of US$8 million from Carnegie, the Ford Foundation, and the U.S. federal government to create and produce a new children's television show.

The show has gone through significant changes in its 40-year history. The format of Sesame Street at first consisted of a combination of commercial television production elements and educational techniques. It was the first time a more realistic setting, an inner city street and neighborhood, was used for a children's program, a choice writer Michael Davis called "unprecedented". At first, each episode was structured like a magazine, but in 1998, as a result of changes in their audience and its viewing habits, the producers changed to a more narrative format. Early in the show's history, the CTW developed what came to be known as "the CTW model," which consisted of a collaboration between educational advisers, researchers, and producers, something Cooney called an "arranged marriage". In 1968, as part of the development of the show, seminars attended by educational and television experts were held. Sesame Street's initial curriculum was developed at this time, and formed the basis of the show's cognitive, affective, and outreach goals.

By its 40th anniversary in 2009, Sesame Street was the fifteenth-highest rated children's television show in the US. It had become the most widely viewed children's television show in the world, with 20 international independent versions, and broadcasts in over 120 countries. A 1996 survey found that 95% of all American preschoolers had watched the show by the time they were three years old. In 2008, it was estimated that 77 million Americans had watched the series as children. As of 2009, Sesame Street has won eight Grammys and 118 Emmys—more than any other children's show.