So far little has been done to explore similarities and differences between radical left parties and other traditionally perceived party families of the left at the societal level. A noticeable gap thus remains in the study of the European radical left: whether and in what ways social divides form the basis of radical left party support. Using data from the fourth round of the European Social Survey (2008), for five West European countries, we investigate radical left party supporters’ socio-demographic and attitudinal characteristics, juxtaposing them with those of social democratic party supporters and green party supporters. Our approach departs from related studies by distinguishing three cognitional operations within the economic left-right axis, that are based on the distinction between ideals and their effects on reality; and by testing for intra-left divides revolving around trust. Based on insights from cleavage research, we devise a number of hypotheses, most of which test positively. Our findings suggest left party families across Western Europe do reflect certain lines of division in society, albeit with qualifications. While structural divides are not found to be significant, there appears to be correspondence between political and attitudinal divides on a three-dimensional space. These concern the cognitive divisions within the economic left-right axis, issues of political trust, and attitudes towards the environment. Our findings have conceptual and empirical implications both for the left and for investigations into cleavage politics.