Sean Llewellyn Williams (born 23 May 1967) is an Australian author of science fiction who lives in Adelaide, South Australia.

That same year, he won the Young Composer's Award for a theme and three variations for string quartet with flute, oboe and trumpet soloists called "Release of Anger".

[3] He is the author of over one hundred and forty published short stories and sixty books, including Twinmaker and (with Garth Nix) the Troubletwisters series.

[citation needed] Williams was Chair of the SA Writers' Centre from 2001 to 2003, and is one of only three lifetime members of that institution.

Williams has also tutored for the Clarion South Workshop, was a previous winner of the Writers of the Future contest, and remains a judge for the same.