The concept of grace has, in the psychology of religion, been largely neglected as a legitimate topic for empirical inquiry. We define grace here as a gift given unconditionally and voluntarily to an undeserving person by an unobligated giver, the giver being either human or divine. We explore the concept of grace within a variety of religious traditions, and then review the small research base on grace. In that the potential ramifications of grace are considerable, greater scientific attention to it seems warranted in both of its dimensions: Perceptions of divine grace received and grace enacted in one’s life. Our working hypothesis is that humanly experienced divine grace has the capacity to profoundly enhance and elevate human flourishing: thus grace fits well within the field of positive psychology, particularly as it intersects with the psychology of religion and spirituality.