Many MMORPG offer players the possibility to become a member of a guild, a hierarchical organization of characters with common objectives. Guild membership can be beneficial to game progress, and offer opportunities for social interaction. In the current study we focus on the MMORPG World of Warcraft (WoW), with the main aim to examine whether guild commitment and players’ intention to remain in their guild can be predicted by players’ satisfaction, investments, and perceptions of alternatives to their guild. To this end, 165 WoW players completed an online questionnaire and answered questions related to their guild membership. They also completed the investment model scale which was reworded so all questions pertained to their guild and their fellow guild members. Results show that satisfaction level, quality of alternatives, and investment size significantly predict commitment level (p’s < .001), which in turn predicted likelihood of participants’ staying with their current guild (p < .001) and the number of guilds they had been a member of in the past (p < .001). Moreover, high levels of guild commitment were indicative of better mental health, whereas weekly hours of game play was negatively related to mental health. In the discussion, we conclude that interdependence theory and the investment model of commitment are applicable to online gaming environments, and we argue that commitment to one’s guild is one factor that could prevent the risks associated with online game play (i.e. problematic use).