Alfred Gerald Caplin (September 28, 1909 – November 5, 1979), better known as Al Capp, was an American cartoonist and humorist best known for the satirical comic strip Li'l Abner, which he created in 1934 and continued writing and (with help from assistants) drawing until 1977. He also wrote the comic strips Abbie an' Slats (in the years 1937–45) and Long Sam (1954). He won the National Cartoonists Society's Reuben Award in 1947 for Cartoonist of the Year, and their 1979 Elzie Segar Award, posthumously for his "unique and outstanding contribution to the profession of cartooning".

Capp's comic strips dealt with urban experiences in the Northern United States until the year he introduced "Li'l Abner". Although Capp was from Connecticut, he spent 43 years writing about the fictional Southern town of Dogpatch, reaching an estimated 60 million readers in more than 900 American newspapers and 100 more papers in 28 countries internationally. M. Thomas Inge says Capp made a large personal fortune through the strip and "had a profound influence on the way the world viewed the American South".

Capp was born in New Haven, Connecticut, of East European Jewish heritage. He was the eldest child of Otto Philip Caplin (1885–1964) and Matilda (Davidson) Caplin (1884–1948). Otto Caplin was a failed businessman and an amateur cartoonist; Al's brothers Elliot and Jerome were also cartoonists, and his sister Madeline was a publicist. Capp's parents were both natives of Latvia whose families had migrated to New Haven in the 1880s. "My mother and father had been brought to this country from Russia when they were infants", wrote Capp in 1978. "Their fathers had found that the great promise of America was true — it was no crime to be a Jew." The Caplins were indigent; Capp recalled stories of his mother going out in the night to sift through ash barrels for reusable bits of coal.

In August 1919, at age nine, Capp was run over by a trolley car and had his left leg amputated above the knee. According to his father Otto's unpublished autobiography, young Capp was not prepared for the amputation beforehand; having been in a coma for days, he suddenly awoke to discover that his leg had been removed. He was eventually given a prosthetic leg but only learned to use it by adopting a slow way of walking which became increasingly painful as he aged. The childhood tragedy of losing a leg likely helped shape Capp's cynical worldview, which was darker and more sardonic than that of most newspaper cartoonists. "I was indignant as hell about that leg," he revealed in a November 1950 interview in Time magazine.

"The secret of how to live without resentment or embarrassment in a world in which I was different from everyone else", Capp philosophically wrote, "was to be indifferent to that difference." The prevailing opinion among his friends was that Capp's Swiftian satire was, to some degree, a creatively channeled, compensatory response to his disability.

Capp's father introduced him to drawing as a form of therapy. He became quite proficient, advancing mostly on his own. Among his earliest influences were Punch cartoonist–illustrator Phil May and American comic strip cartoonists Tad Dorgan, Cliff Sterrett, Rube Goldberg, Rudolph Dirks, Fred Opper, Billy DeBeck, George McManus, and Milt Gross. At about this same time, Capp became a voracious reader. According to Capp's brother Elliot, Alfred had finished all of Shakespeare and George Bernard Shaw before he was 13 years old. Among his childhood favorites were Dickens, Smollett, Mark Twain, Booth Tarkington, and later, Robert Benchley and S. J. Perelman.

Capp spent five years at Bridgeport High School in Bridgeport, Connecticut, without receiving a diploma. He liked to joke about how he failed geometry for nine straight terms. His formal training came from a series of art schools in the Northeast. Attending three of them in rapid succession, the impoverished Capp was thrown out of each for nonpayment of tuition—the Boston Museum School of Fine Arts, the Pennsylvania Academy of the Fine Arts, and Designers Art School in Boston—the last before launching his career. Capp already had decided to become a cartoonist. "I heard that Bud Fisher (creator of Mutt and Jeff) got $3,000 a week and was constantly marrying French countesses", Capp said. "I decided that was for me."

In early 1932, Capp hitchhiked to New York City. He lived in "airless rat holes" in Greenwich Village and turned out advertising strips at $2 each while scouring the city hunting for jobs. He eventually found work at the Associated Press when he was 23 years old. By March 1932, Capp was drawing Colonel Gilfeather, a single-panel, AP-owned property created in 1930 by Dick Dorgan. Capp changed the focus and title to Mister Gilfeather but soon grew to hate the feature. He left the Associated Press in September 1932. Before leaving, he met Milton Caniff and the two became lifelong friends. Capp moved to Boston and married Catherine Wingate Cameron, whom he had met earlier in art class. She died in 2006 at the age of 96.