ABSTRACT The 2022 full-scale Russian invasion into Ukraine challenged the political parties of the radical left and right that have traditionally been sympathetic to Russia. This paper examines the positions on the Russian war against Ukraine of radical left members of the 9th European Parliament (2019–2024), based on their voting behavior in the first year since the start of the full-scale invasion. The data show that the radical left is most divided over sanctions. In contrast, MEPs from the 18 radical left parties under study are highly united in their support of international law. The divisions among radical left MEPs correlate weakly with the geographical distance to Russia and with their parties’ position on the left/right-axis, but more strongly with parties’ position on socio-cultural questions: Socio-culturally progressive parties are more inclined to support an assertive stance towards Putin’s authoritarian and traditionalist Russia than socio-culturally conservative ones.