The process of globalization and the rise of information and telecommunication technology have significantly affected global and South Eastern -SEE security. On one hand, thanks to the development of these technologies and geopolitical dynamics, the region of SEE is becoming more interconnected, interrelated and shaped by modern infrastructures that enable respective SEE countries’ commodities, prosperity and competitiveness. On the other hand, like in the rest of the world, these processes and dynamics have increased unpredictability, complexity and threats to the SEE security in the context of modern terrorism. At the same time, the recent history of violent conflicts, social stability challenges, Euro-Atlantic ambitions, support to the “global war on terror” and the increased presence of radical religious groups and individuals in the region of SEE are variables that further affect its security. Today, modern terrorist groups and individuals exploit cyberspace to achieve strategic advantages against the mightier enemies. Given that their agenda is violent, abstract and apocalyptic protection of the critical information infrastructure has become one of the main concerns for NATO and its allies. Therefore the article explores how and in which way terrorists' use of cyberspace could affect critical information infrastructure in the region of SEE. To achieve this, the article first explains contemporary terrorists' objectives around the globe and compares them with the objectives that these actors have in the region of SEE. In this context the article briefly explains the development and achievements of the ICT sector in the region of SEE and analyzes them into the context of cyber-based threats posed by modern terrorism. Then the article provides an assessment of how the terrorists' use of a cyberspace affects critical information infrastructures in the region of SEE.