Is it SFWA or SFFWA?

The reason one sometimes sees SFWA and sometimes SFFWA, both referring to the same organization, is that for a long time there was no official agreement on which was correct.

In 1965 the organization was named Science Fiction Writers of America and abbreviated SFWA (pronounced SEFwa or sometimes SIFwa, though Damon says the latter sounds like a disease). In those days the distinction between science fiction and fantasy was much less important and either was generally assumed to encompass both.

When the distinction became more important, and there was some question as to whether fantasy works could be used for membership qualification, the name was changed to Science Fiction and Fantasy Writers of America. Some wrote it as Science-fiction and Fantasy Writers of America in an effort to keep the traditional abbreviation; but that's admittedly a rather silly way to write it and few people did. Many simply added the extra F to the acronym; but as the referendum that added "and Fantasy" to the name lumped an extra F in the acronym into the same question, some insisted that they had voted for it only because they couldn't vote for "and Fantasy" without it, and they darn well weren't going to use it.

For quite some time the acronym remained a matter for contention. There were good arguments on both sides. Perhaps the strongest for SFFWA was that tradition or no, the name is spelled with two Fs. Perhaps the strongest for the traditional SFWA was, "One F, because we're all in it together."

In 1996 a referendum was taken, and SFWA won by a strong majority. That is now the official abbreviation, though the other may continue to be used by some, if only for the sake of argument.