In this chapter, we give an overview about theoretical and empirical work on forgiveness from a lifespan development perspective. First, we give an example of an interpersonal transgression to introduce the main terms and definitions of this chapter. This helps us to describe different perspectives and levels of analysis. Second, we conceptualize situation-specific forgiveness as a process of change and dispositional forgiveness as a trait. Third, we make the case that a lifespan development perspective on forgiveness is important for scientific psychological research and particularly for the field of justice research. Fourth, we present theoretical and empirical research on forgiveness across the adult lifespan. Finally, we discuss practical implications of a lifespan development perspective on forgiveness.