Violent events fuel from both sides of the political spectrum. Despite divergences in the ideology, causes, uses and meanings of violence, the two camps – the far left and the far left – share common grounds: violent actors express hostility against parliamentarism, oppose liberal democracy and exhibit intolerance towards their political and ideological opponents. In the vast landscape of political violence, its organised component is of high significance. “Waves” of terrorism are "composed of organizations" and they decline when organizations are no longer successful. Terrorist organizations rely on structure for security, target selection and effectiveness. They need an ideological belief system, conviction, as well as material resources to exercise influence and perform operations. Despite the complex and important role that organisations play on politically violent groups’ behaviours, exploring their structure and operational rules before their end, entails challenges linked to their clandestine nature, as reliable information remains difficult to collect. Drawing evidence from the Political Violence in Greece (PVGR) dataset (Rori, Georgiadou and Roumanias 2022a, 2022b) enriched with data of a longer period of time, this paper focuses on organised political violence, shedding light on the physiognomy of organisations of both edges of the Greek extremist spectrum: the far right and the far left. The timespan of the paper covers a period of 18 years, ranging from 2002 to 2019. By exploring their resources, targets, means of attack and narrative, we find similarities and differences and propose a typology informed by more fine-grained categories, covering the vast majority of the internal supply-side factors.