Advocacy and its direct and indirect advocacy tactics have been heavily researched within nonprofit studies. However, next to influencing institutional elites, nonprofits could strive toward other political goals as well. Based on our current understanding of advocacy, we have uncovered another form of nonprofit politics: ‘politicization’ of the public sphere. In this study, we include both politicization and advocacy, and analyze the extent to which advocacy and politicization can be considered as two separate forms. Moreover, we examine the explanatory value of organizational size and age, public and market income and institutional field of activity, within the neo-corporatist context of Flanders, the northern region of Belgium. Making use of a large-N survey database of Flemish nonprofits, our findings show that: (a) advocacy is present to a larger degree than politicization, (b) advocacy and politicization are significantly correlated and (c) institutional field of activity and public income are important explanatory variables.