Intentional communities are bodies of mass intentions — spiritual entities — that consciously strive for sustainable ways of being. The communities provide structures, practices, and ideologies to fulfill members’ needs. This study proposes that a framework of spiritual development may serve as a means to evaluate intentional communities on the degree of their sustainability. Spirituality, noted in the literature as a characteristic of intentional communities, has not previously been articulated as a criterion for community success. In the paper, four stages of spiritual development — undeveloped, developing, developed, and fully sustainable — will be presented, as well as three dimensions of community sustainability — structural, practical, and ideological. The study finds that the stage of development of three rural intentional communities in the United States — East Wind, The Farm as well as its constituent Ecovillage Training Center, and Ananda Village — correlates with the degree of their sustainability. The proposed framework suggests that intentional communities may be unified across geographical and historical contexts on the basis of shared spirituality; it also enables the nonhierarchical, sympathetic understanding of intentional communities as varying in development. Future researchers and community members may consider the strength of correlation between spirituality and sustainability in forming intentional communities.