There is much debate in community psychology literature as to the dimensions underlying the construct psychological sense of community (PSOC). One of the few theoretical discussions is that of McMillan and Chavis (1986), who hypothesized four dimensions: Belonging; Fulfillment of Needs; Influence; and Shared Emotional Connection. Debate has also emerged regarding the role of identification within PSOC. However, few studies have explored the place of identification in PSOC. In addition, while PSOC has been applied to both communities of interest and geographical communities, to date little research has compared a single group’s PSOC with a community of interest to their PSOC with their geographical communities. The current study explored PSOC with participants’ interest and geographical communities in a sample (N = 359) of members of science fiction fandom, a community of interest with membership from all over the world. Support emerged for McMillan and Chavis' (1986) four dimensions of PSOC, both within participants’ PSOC with their geographical communities and with their community of interest, with the addition of a fifth dimension, that of Conscious Identification. All dimensions emerged as significant predictors of overall sense of community in both community types. Participants reported higher levels of global PSOC with fandom than with their geographical communities, a pattern that also emerged across all factors separately. These results, and implications for PSOC research, are discussed.