Horror Writers Association (HWA)
The HWA is a worldwide organization of writers and publishing professionals dedicated to promoting the interests of writers of Horror and Dark Fantasy.
A science-fiction, fantasy, and horror club for lesbians, gay men, bisexuals, transsexuals and their friends in the Washington DC area.
Science Fiction and Fantasy Writers of America, Inc.
Science Fiction and Fantasy Writers of America, Inc., is a non-profit organization whose primary purpose is to help SF/F authors deal effectively with agents, editors, anthologists.
World Science Fiction Society
WSFS chooses the recipients of the annual Hugo Awards (Science Fiction Achievement Awards) and runs the annual World Science Fiction Conventions (the Worldcons).