This article investigates the formal and informal factors behind the persistence of judicial oligarchies in post-communist countries despite large-scale reforms. This case study on Georgia reveals that formal positions of power in these judiciaries can be monopolized by a close-knit group, with a handful of influential judges (i.e. judicial oligarchs) at the top of its hierarchical structure. Drawing on in-depth interviews with sitting as well as former judges and other stakeholders of reform processes, the article attributes the failure to dismantle the rule of judicial oligarchs at least partly to legislative flaws and loopholes. More importantly, it warns about the reliance of judicial oligarchs on informal rules and practices to undermine formal rules and procedures meant to facilitate the meaningful participation of all judges in governing the judiciary. It uncovers informal mechanisms allowing the network of powerful judges to suppress the emergence of competing judicial networks and cement itself into leadership positions. Finally, the article reflects on the implications of these findings for designing and implementing judicial reforms in Georgia and beyond.