I Love Lucy is an American sitcom that originally aired on CBS from October 15, 1951, to May 6, 1957, with a total of 180 half-hour episodes spanning six seasons. The series starred Lucille Ball and her husband Desi Arnaz, along with Vivian Vance and William Frawley, and follows the life of Lucy Ricardo (Ball), a young, middle-class housewife living in New York City, who often concocts plans with her best friends and landlords, Ethel and Fred Mertz (Vance and Frawley), to appear alongside her bandleader husband, Ricky Ricardo (Arnaz), in his nightclub. Lucy is depicted trying numerous schemes to mingle with and be a part of show business. After the series ended in 1957, a modified version of the show continued for three more seasons, with 13 one-hour specials, which ran from 1957 to 1960. It was first known as The Lucille Ball–Desi Arnaz Show, and later, in reruns, as The Lucy–Desi Comedy Hour.

I Love Lucy became the most-watched show in the United States in four of its six seasons and it was the first to end its run at the top of the Nielsen ratings. As of 2011, episodes of the show have been syndicated in dozens of languages across the world and remain popular with an American audience of 40 million each year. A colorized version of its Christmas episode attracted more than eight million viewers when CBS aired it in prime time in 2013, 62 years after the show premiered.

The show – which was the first scripted television program to be filmed on 35 mm film in front of a studio audience, by cinematographer Karl Freund – won five Emmy Awards and received many nominations and honors. It was the first show to feature an ensemble cast. As such, it is often regarded as one of the most influential television programs in history. In 2012, it was voted the 'Best TV Show of All Time' in a survey conducted by ABC News and People magazine. In 2013, the Writers Guild of America ranked it #12 on their list of the 101 Best Written TV Series.