Looney Tunes is an American media franchise produced and distributed by Warner Bros. The franchise began as a series of animated short films that originally ran from 1930 to 1969, alongside its spin-off series Merrie Melodies, during the golden age of American animation. Following a revival in the late 1970s, new shorts were released theatrically as recently as 2014. The two series introduced a large cast of characters, including Bugs Bunny, Daffy Duck, Elmer Fudd and Porky Pig. The term Looney Tunes has since been expanded to also refer to the characters themselves.

Looney Tunes and Merrie Melodies were initially produced by Leon Schlesinger and animators Hugh Harman and Rudolf Ising from 1930 to 1933. Schlesinger assumed full production from 1933 until he sold his studio to Warner Bros. in 1944, after which it was renamed Warner Bros. Cartoons. The Looney Tunes title was inspired by that of Walt Disney's Silly Symphonies. The shorts initially showcased musical compositions owned by Warner's music publishing interests through the adventures of such characters as Bosko and Buddy. However, the shorts gained a higher profile upon the debuts of directors Tex Avery, Friz Freleng, Chuck Jones, Bob Clampett, and Robert McKimson, and voice actor Mel Blanc later in the decade. Porky Pig and Daffy Duck became the featured Looney Tunes characters, while Merrie Melodies featured one-shot cartoons and minor recurring characters.

After Bugs Bunny became popular in the Merrie Melodies shorts of the early 1940s, Looney Tunes moved from black-and-white to color production between 1942 and 1943 (Merrie Melodies having already been in color since 1934). The two series gradually lost their distinctions, and shorts were assigned to each series arbitrarily. From 1942 to 1964, Looney Tunes and Merrie Melodies were the most popular animated shorts in movie theaters.

Looney Tunes has become one of the highest-grossing media franchises of all time, spawning several television series, feature films, comic books, music albums, video games, and amusement park rides. Many of the characters have made and continue to make cameo appearances in television shows, films, and other media. Bugs Bunny, in particular, is regarded as a cultural icon as well as the mascot of Warner Bros. Pictures, and has a star on the Hollywood Walk of Fame. Many Looney Tunes and Merrie Melodies films are ranked among the greatest animated cartoons of all time, and five of them have won Academy Awards. In 2013, TV Guide counted Looney Tunes as the third greatest television cartoon series of all time, behind The Simpsons and The Flintstones, the latter of which also featured the voice talents of Mel Blanc and Bea Benaderet.

Looney Tunes and Merrie Melodies were so named as a reference to Disney's Silly Symphonies and were initially developed to showcase tracks from Warner Bros.' extensive music library; the title of the first Looney Tunes short, Sinkin' in the Bathtub (1930), is a pun on Singin' in the Bathtub. Between 1934 and 1943, Merrie Melodies were produced in color and Looney Tunes in black-and-white. After 1943, both series were produced in color and became virtually indistinguishable, varying only in their opening theme music and titles. Both series made use of the various Warner Bros. characters. By 1937, the theme music for Looney Tunes was "The Merry-Go-Round Broke Down" by Cliff Friend and Dave Franklin, and the theme music for Merrie Melodies was an adaptation of "Merrily We Roll Along" by Charles Tobias, Murray Mencher and Eddie Cantor.

In 1929, to compete against Walt Disney's Mickey Mouse short cartoons, Warner Bros. became interested in developing a series of animated shorts to promote their music. They had recently acquired Brunswick Records along with four music publishers for US$28 million (equivalent to $527 million in 2024) and were eager to promote this material for the sales of sheet music and phonograph records. Warner made a deal with Leon Schlesinger to produce cartoons for them. Schlesinger hired Rudolf Ising and Hugh Harman to produce a series of cartoons, impressed by their 1929 pilot film, Bosko, The Talk-Ink Kid. The first Looney Tunes short was Sinkin' in the Bathtub starring Bosko, which was released in 1930.

When Harman and Ising left Warner Bros. in 1933 over a budget dispute with Schlesinger, they took with them all the rights of the characters they had created. A new character called Buddy became the only star of the Looney Tunes series for a couple of years, but quickly became unpopular.

New directors including Tex Avery, Friz Freleng and Bob Clampett were brought in or promoted to work with animators in the Schlesinger studio, with Avery's unit housed in a bungalow which the animators dubbed "Termite Terrace." In 1935, Porky Pig, the first major Looney Tunes star, made his debut in the Merrie Melodies cartoon I Haven't Got a Hat, directed by Friz Freleng, featuring an ensemble of characters headed by Beans the Cat. However, after Avery's Looney Tune debut Gold Diggers of '49 it was Porky who emerged as the star instead of Beans. The ensemble characters of I Haven't Got a Hat, such as Oliver Owl and the twin dogs Ham and Ex, were quickly dropped. Beans would be phased out as well by mid-1936, leaving Porky as the only star of the Schlesinger studio.