NASFiC, a.k.a. the North American Science Fiction Convention, is a science fiction convention scheduled only during years where the Worldcon is being held outside of the North American continent. NASFiC bids voted on by the Worldcon (or NASFiC if one exists) membership the year after a non-North American Worldcon site has been selected. As of 2014, this is one year in advance of a potential NASFiC.
Activities at a NASFiC parallel those seen at Worldcon, but may differ with each convention committee. The convention may be held as an individual event or in conjunction with another convention. It generally occurs near the time of the Worldcon, but not in direct competition with it. The name NASFiC is owned by the World Science Fiction Society (WSFS).
The late Robert Sacks led a movement to separate NASFiC from the World Science Fiction Society, similar to Eurocon, but WSFS has
chosen to keep NASFiC under its own aegis.