New parties situated to the left of social democracy have become increasingly relevant in the EU's political landscape in recent years, particularly after the start of the eurozone crisis. In 2015 we witnessed some of these parties making significant electoral breakthroughs, particularly Syriza, who came to power in Greece on an anti austerity platform, a success followed, however, by a compromise with the country's international creditors. The present paper argues that these new parties form a relatively homogeneous movement that emerged at the turn of the century. For not only they share a broadly similar agenda and strategy but, indeed, are engaged in a process of transnational cooperation never witnessed before on the radical left at the EU level. This process takes place through new transnational structures, particularly the Party of the European Left. Thus, the paper aims to provide an overview of this new European left, with a focus on how the broadly common traits of the variousnew left parties are reflected at a transnational level by their main transnational structure, the Party of the European Left. The paper looks then at 2015, the most tumultuous year yet for the new European left, focusing on Syriza's compromise and how the movement has reacted so far at a transnational level to that compromise.