Ideological polarization is a prominent research topic. The literature has focused especially on public opinion, as well as on the legislative and executive branches, when analyzing its causes and consequences. However, less attention has been paid to whether courts are also affected, particularly in the European context. This paper reflects on judicial polarization—extending the concept of ideological polarization to courts—and contributes to the literature by providing five indicators for analysis: dissent rate, judges' ideology, the ideology of the median judge, whether ideological distance with applicants explains rulings, and whether ideological distance between judges explains agreement. Then, these indicators are correlated with Dalton's (2008) index of polarization to explore the relationship between polarization in court and parliament. The analysis examines decisions by judges of the Spanish Constitutional Court from 1980 to 2023. It begins by inferring judges' ideology through indifference-point estimation. A novel validation of these estimates is then performed—using the appointing party's ideology, as coded by the Comparative Manifesto Project, as a proxy—before incorporate them into the analysis. While constitutional courts in parliamentary democracies are often perceived as isolated from partisan dynamics and resistant to polarization, this study challenges that assumption.