Recent years have seen a growing volume of research on citations between courts from different countries. This article fills a gap in the current literature by presenting and analysing cross-citations between the highest domestic courts responsible for matters of private law in the EU from 2000 to 2018. It addresses two main questions: first, to what extent do judges cite foreign case law in their decisions? Second, what may explain the varying levels of engagement of supreme courts with foreign case law? Our findings offer a mixed result as to the nature and frequency of such cross-citations. Overall, we identify 2984 cross-citations; yet, only in few instances do we find a reciprocal relationship between the supreme courts of two countries, while more generally an asymmetric picture emerges. The article also discusses whether problems with the ease of access to court decisions may partly be responsible for limitations in the use of cross-citations.