The risk posed by terrorist use of cyber technology and cyber terrorism have been of great concern to politicians, decision makers, security officials. This article studies terrorist use of cyber technology and cyber terrorism along with history of cyber-terrorism. Moreover some concepts such as between cyber-crime, cyber-terrorism, cyber-warfare and hactivism will be analysed. Furthermore, the challenges faced by international organisations in tackling cyber terrorism will be discussed; measures introduced in some countries to address cyber terrorism treats are presented as well as discussions on the present and the future treat posed by cyber terrorism and terrorist use of cyber technology.