This chapter discusses the current situation of social enterprise (SE) in the four countries under consideration. It analyses the institutional background within which social enterprises emerged and operate. The chapter focuses on their ecosystem. Some traditions that have shaped social enterprises derived from voluntary organisations have existed in Poland, Hungary, the Czech Republic and Croatia since the Middle Ages. In Croatia, the Act on Social Organisations and Citizens’ Associations was adopted in 1982. The period of the 1990s was marked by the significant role played by foreign funding in all the countries analysed. In Poland, the Czech Republic and Hungary, the second half of the 1990s and the early 2000s were characterised by further institutionalisation of non-profit organisations. In the countries studied, different approaches can be distinguished regarding the legal recognition of social enterprises. None of the analysed country has yet defined the role of social enterprises in its public-welfare system.