Helios was a science fiction fanzine by Sam Moskowitz.
The first issue of Helios was published in June 1937 in Newark, New Jersey, U.S.A., edited by Sam Moskowitz and Alex Osheroff. It was a hectographed, stapled publication. Six issues were released, with issues two to six edited solely by Moskowitz. The last issue appeared in May 1938.
Contributors included Robert Sanders Shaw, Willis C. Conover (Science-Fantasy Correspondent), Morris Scott Dollens (Science-Fiction Collector), Litterio B. Farcasi (The Golden Atom), John Russell Fearn, Chester Fein, Nils Helmer Frome (Supramundane Stories), David H. Keller, Fred Lawrence, John Bee Myshell, Alex Osheroff, J. Michael Rosenblum (Futurian War Digest), Wilson Sheperd, Clark Ashton Smith, Louis C. Smith, Corwin Stickney (Amateur Correspondent), William Sykora, James V. Taurasi (Cosmic Tales), Robert G. Thompson, Raymond Van Houten (Tesseract), Richard Wilson, Jr., and Donald Wollheim (The Phantagraph).
After Helios ended in May 1938, Sam Moskowitz immediately began a new fanzine that same year called New Fandom, released in September-October 1938.