This study examines how trust is related to online social institutions, self-disclosure, mode of communication, and message privacy in a popular MMOG, Everquest II. The findings, based on survey and behavioral data from over 3,500 players, illustrate how MMOGs may support trust development. Trust was higher within closer social circles: trust was highest in teammates, followed by other players across the game, followed by others online. Self-disclosure was positively related to trust of teammates and others in the game, while voice chat was only related to teammate trust. These findings indicate that social structures and communication processes contribute to trust development in MMOGs, supporting the claim that these online spaces provide social support that is unavailable in other societal realms.