Although accountability is touched on in nearly every account of current higher education developments (HE), only a few HE scholars have attempted to further theorize accountability, its forms, implications, and practical significance. In this chapter, we attempt to advance the debate by focusing on European HE in the age of Bologna, international rankings, massification, and underfunding. We begin our analysis by addressing the manifold socio-economic forces which have put accountability centre stage in contemporary HE discourse and reforms. We then outline numerous state-of-the-art conceptualizations of accountability in general, and in HE specifically. Following the lead of Huisman and Currie (2004), we wish to move beyond normative statements and generalized descriptions by analysing the emergence of ‘accountability regimes’ in four large European countries — Germany (North-Rhine Westphalia), France, Poland, and Romania — with distinctly different paths of development in HE. The analysis allows us to identify cross-national cases of convergence and divergence in the emergence of accountability regimes.