This chapter explores what party membership means in the Netherlands and subsequently presents some findings of the research on Dutch party membership. The Freedom Party (PVV) only has a single individual party member, that is, party leader Geert Wilders, and therefore can hardly be regarded a true membership party. For this reason the Freedom Party is discussed only in passing, with the chapter concentrating on the ten membership parties that were represented in the Second Chamber after the general elections of September 2012. The chapter presents the criteria of party membership and the rights and obligations of individual party members. It shows how membership figures have developed over time and subsequently presents what party membership surveys tell people about the motives, activities and opinions of individual Dutch party members which has a high degree of electoral volatility, both small and big parties plays an important role in the formation of government coalitions and in the creation of political stability.