City Lights is a 1931 American synchronized sound romantic comedy-drama film written, produced, directed by, and starring Charlie Chaplin. While the film has no audible dialog, it was released with a synchronized musical score with sound effects. The story follows the misadventures of Chaplin's Tramp as he falls in love with a blind woman (Virginia Cherrill) and develops a turbulent friendship with an alcoholic millionaire (Harry Myers).

Although talking pictures (or films with recorded dialogue) were on the rise when Chaplin started developing the script in 1928, he decided to continue working without dialogue only incorporating sound with the use of a synchronized musical score with sound effects. Filming started in December 1928 and ended in September 1930. City Lights marked the first time Chaplin composed the film score to one of his productions and it was written in six weeks with Arthur Johnston. The main theme, used as a leitmotif for the blind flower girl, is the song "La Violetera" ("Who'll Buy my Violets") from Spanish composer José Padilla. Chaplin lost a lawsuit to Padilla for not crediting him.

City Lights was immediately successful upon release on March 7, 1931, with positive reviews and worldwide rentals of more than $4 million. Today, many critics consider it not only the highest accomplishment of Chaplin's career, but one of the greatest films of all time. Chaplin biographer Jeffrey Vance believes "City Lights is not only Charles Chaplin's masterpiece; it is an act of defiance" as it premiered four years into the era of sound films which began with the premiere of The Jazz Singer (1927). In 1991, the Library of Congress selected City Lights for preservation in the United States National Film Registry as being "culturally, historically, or aesthetically significant". In 2007, the American Film Institute ranked it 11th on its list of the best American films ever made. In 1949, the critic James Agee called the film's final scene "the greatest single piece of acting ever committed to celluloid".

The unveiling of a new monument to "Peace and Prosperity" reveals the Little Tramp asleep in the lap of one of the sculpted figures. He escapes the assembly's fury and roams the city.

The Tramp encounters a flower girl on a street corner. He is instantly smitten and realizes she is blind while buying a flower from her. The woman mistakes him for a wealthy man when the door of an automobile slams shut as he departs.

That evening, the Tramp saves a drunken millionaire from suicide. The millionaire takes the Tramp, his new best friend, back to his mansion for champagne, then to a party. After helping the millionaire home the next morning, he sees the flower girl en route to her street corner. He gets some money from the millionaire, buys all her flowers and drives her home in the millionaire's car. After the Tramp leaves, the flower girl tells her grandmother about her kind, wealthy friend. Meanwhile, the Tramp returns to the mansion, where the millionaire – now sober – does not remember him and throws him out. Later that day, the millionaire is once again intoxicated and, seeing the Tramp on the street, invites him home for a lavish party. However, the millionaire is sober again the next morning and again kicks the Tramp out.

Finding that the woman is not at her usual corner, the Tramp goes to her apartment and overhears a doctor telling the grandmother that she has a fever. Determined to help, the Tramp takes a job as a street sweeper. On his lunch break, he brings her groceries. To entertain her, he reads a newspaper aloud, including a story about a Viennese doctor's blindness cure. "Wonderful, then I'll be able to see you," says the woman. He also finds an eviction notice the woman's grandmother has hidden. As he leaves, he pledges to pay the rent. However, he is fired for frequently being late.

A boxer convinces him to fight in a fixed match and split the prize money. However, the boxer is replaced at the last minute by a no-nonsense fighter who knocks the Tramp out despite the Tramp's nimble evasions.