Thor debuted in the science fiction/fantasy anthology title Journey into Mystery #83 (cover-date Aug. 1962), and was created by editor-plotter Stan Lee, scripter Larry Lieber, and penciller-plotter Jack Kirby. A different version of the mythological Thor had appeared previously in Venus #12-13 (Feb.-April 1951).
In a 1984 interview Kirby said “I did a version of Thor for D.C. in the Fifties before I did him for Marvel. I created Thor at Marvel because I was forever enamored of legends, which is why I knew about Balder, Heimdall, and Odin. I tried to update Thor and put him into a superhero costume, but he was still Thor.” And in a 1992 interview, Kirby said “[I] knew the Thor legends very well, but I wanted to modernize them. I felt that might be a new thing for comics, taking the old legends and modernizing them.”
Journey into Mystery was retitled Thor (per the indicia, or The Mighty Thor per most covers) with issue #126 (March 1966). “Tales of Asgard” was replaced by a five-page featurette starring the Inhumans from #146–152 (Nov. 1967 – May 1968), after which featurettes were dropped and the Thor stories expanded to Marvel’s then-standard 20-page length.