Donald L. Heck (January 2, 1929 – February 23, 1995) was an American comics artist best known for co-creating the Marvel Comics characters Iron Man, the Wasp, Black Widow, Hawkeye and Wonder Man and for his long run penciling the Marvel superhero-team series The Avengers during the 1960s Silver Age of comic books.

Heck was born in the Jamaica neighborhood of Queens, New York City, the son of Bertha and John Heck, of German descent. Heck learned art through correspondence courses as well as at Woodrow Wilson Vocational High School in Jamaica and at a community college in Brooklyn. He continued with an impromptu art education in December 1949 when at the recommendation of a college friend he landed a job at Harvey Comics. There he repurposed newspaper comic strip Photostats into comic-book form – including the work of Heck's idol, famed cartoonist Milton Caniff.

Heck remained at Harvey, where one co-worker in the production department was future comics artist Pete Morisi, for two-and-a-half years. When a Harvey employee, Allen Hardy, broke off “to start his own line, Media Comics [sic; actually Comic Media], in 1952," Heck recalled in 1993, Hardy “called me up and asked me to join." Heck's first known comics work appeared in two Comic Media titles both cover-dated September 1952: the war comic War Fury #1, for which he penciled and inked the cover and the eight-page story "The Unconquered", by an unknown writer; and the cover and the six-page story "Hitler's Head", also by an unknown writer, in the horror comic Weird Terror #1. Heck's work continued to appear in those titles and in the horror anthology Horrific, for which he designed the logo; the adventure-drama anthology Danger; the Western anthology Death Valley; and other titles through the company's demise in late 1954.

Heck also did freelance assignments for Quality Comics, Hillman Comics, and Toby Press. For publisher U.S. Pictorial in 1955, he drew the one-shot Captain Gallant of the Foreign Legion, a TV tie-in comic based on the 1955–57 syndicated, live-action kids' show of that name.

Through his old Harvey Comics colleague Pete Morisi, Heck in 1954 met Marvel Comics’ Stan Lee, then editor-in-chief and art director of Marvel's 1950 predecessor, Atlas Comics. As Heck recalled

Pete Morisi, who worked at Media at the same time [I did], had been to Stan Lee's office, and he had brought his [art portfolio]. One of my stories was in there. and Stan kept going back to my story, saying, "This is the way you should have done it." Pete said. "Look, if you want Don Heck to come up here, he's looking for work, too. I'll tell him you're interested." Stan said, "Well, if he happened to walk up here, I might have a story for him." So I went up there on a Wednesday afternoon. Stan never saw anybody on Wednesdays, and he never saw anybody in the afternoon. But he came out. He looked at the first two pages and said, "Aw, hell, I know what your stuff looks like. Come on in. I got a story for you."

Heck became an Atlas staff artist on September 1, 1954; his first known work for the company was the five-page horror story "Werewolf Beware" in Mystery Tales #25 (Jan. 1955), though Heck in 1993 recalled, "The first job I did was about a whale breaking a ship apart. Then I did [the submarine-crew feature] 'Torpedo Taylor' for Navy Combat," drawing that five- or six-page feature in issues #1–14 and 16 (June 1955–Aug. 1957, Feb. 1958) and, oddly, doing one page of a five-page story finished by Joe Maneely in issue #19 (Aug. 1958). Until Atlas' 1957 business retrenchment – when it let go of most of its staff and freelancers and Heck spent a year drawing model airplane views for Berkeley Models – Heck contributed dozens of war comics stories and Westerns plus a smattering of jungle and science-fiction/fantasy tales.

Atlas began revamping in late 1958 with the arrival of artist Jack Kirby, a comics legend whose career was also in need of revamping, and who threw himself into the anthological science fiction, supernatural mystery, and giant-monster stories of what would become known as "pre-superhero Marvel." Heck returned alongside other soon-to-be-famous names of Marvel Comics' 1960s emergence as a pop culture phenomenon, making his first splash with the cover of Tales of Suspense #1 (Jan. 1959), one of the very few Atlas/Marvel covers of that time not drawn by Kirby. In the years immediately preceding the arrival of the Fantastic Four, Spider-Man, and the other popular heroes of Marvel's ascendancy, Heck gave atmospheric rendering to numerous science fiction / fantasy stories in that comic as well as in sister publications Strange Tales, Tales to Astonish, Strange Worlds, World of Fantasy, and Journey into Mystery. Heck also contributed to such Atlas/Marvel romance comics as Love Romances and My Own Romance.