In this chapter, we will provide a theoretical overview to answer the question of why some people in some countries donate more often and higher amounts to nonprofit organizations than others. There are two types of answers to this question. First of all, aggregated individual-level differences between people can account for cross-national differences in philanthropic behavior. If people in some countries on average have more of the individual factors known to promote philanthropic giving, this can explain why people in that country are more likely to give and give higher amounts. These are compositional explanations. An example of a compositional explanation is educational level. We know that people who are higher educated display higher giving behavior (Brown & Ferris, 2007; Bekkers & Wiepking, 2011b) among others because they have more resources available in the form of income and knowledge about nonprofit organizations and their needs. If people in a country are on average higher educated, this can explain why people in that country are more generous donors. Other aggregated individual-level factors that are known to influence philanthropic behavior are, for example, financial, human and social resources and religious, political and prosocial values