Research findings point consistently to the conclusion that forgiveness is positively associated with well-being, quality of life, life satisfaction, gratitude, optimism, hope, trust, self-worth and positive beliefs. Forgiveness also affects and is negatively associated with emotional distress and negative affective states such as depression, anger, vengeance, anxiety, somatic symptoms, guilt and vulnerability. Gratitude, like forgiveness, has been shown to have positive associations with well-being, positive affect and emotions, happiness, trust, altruism, life satisfaction, forgiveness, vitality, spirituality, optimism and positive beliefs. Gratitude also has negative associations with emotional distress and negative affective states such as hostility, anger, aggression, depression, anxiety, stress and vulnerability. This integrative review of the literature also points out that forgiveness and (to a somewhat lesser extent) gratitude, are multidimensional constructs. The research to date has, however, implied an underlying duality in the constructs of forgiveness and gratitude and has usually been conducted from a non-spiritual focus. Moreover, the research is largely focused on correlations, leaving the direction of causality somewhat unclear. This paper reviews the relevant literature and discusses how a non-dualistic, spirituality oriented theory and research guided by that theory would potentially contribute a great deal to the field.