Sheila Williams is an American science fiction editor who is the editor of Asimov's Science Fiction magazine.

Asimov's Science Fiction is an American science fiction magazine edited by Sheila Williams and published by Dell Magazines, which is owned by Penny Press. It was launched as a quarterly by Davis Publications in 1977, after obtaining Isaac Asimov's consent for the use of his name. It was originally titled Isaac Asimov's Science Fiction Magazine, and was quickly successful, reaching a circulation of over 100,000 within a year, and switching to monthly publication within a couple of years. George H. Scithers, the first editor, published many new writers who went on to be successful in the genre. Scithers favored traditional stories without sex or obscenity; along with frequent humorous stories, this gave Asimov's a reputation for printing juvenile fiction, despite its success. Asimov was not part of the editorial team, but wrote editorials for the magazine.