Compared to the longstanding literature on the process of forgiveness or state forgiveness, relatively less research has focused on how to develop a dispositional tendency to forgive others, known as forgivingness. This holds particularly true with respect to adulthood, which has been typically viewed as a period of personality consistency rather than change. In the current paper, we begin by discussing forgivingness and its potential for promoting adult well-being. Next, we describe three literatures that help us understand possible influences on forgivingness development in adulthood, which focus on (a) how adults respond to their changing societal roles, (b) the choices they make with respect to social and emotional regulation, and (c) their relationship attachment models. Finally, we conclude by presenting important questions for the future research on this personality trait.