This research attempts to quantify the major factors behind terrorism in the sample of 115 countries for period of 1990 to 2012. In this research we find that the causes behind the terrorism are heterogeneous across the various regions of the world. We used negative binomial model as our data was number of counts for terrorism. There is heterogeneity in structural variables including economic deprivation, demographic changes, socio-economic conditions, government stability, global order, internal conflict, and colonization in all regions of world. This heterogeneity is the main reason behind the fluctuation in number of terrorism incidents. Among all incorporated variables, different variables have not only different impact for all regions but also their significance is varying in nature. The impact of economic deprivation on terrorism in different regions is not appropriate. The negative relation of demographic changes or modernization with terrorism is higher in Sub Saharan region then the impact of socio economic conditions which is more important there. In Middle East, negative impact of modernization and religion in politics are prime factors behind terrorism. Similarly, internal conflict, government stability and religion in politics are major determinants of terrorism in Asian region. There is a positive impact of demographic changes in American and European region. We find that colonization has link with terrorism but it is not strong enough for considering it one of major cause. The religion in politics is significant cause of terrorism in American region. The effect of global order on terrorism is high in American region then in European region and almost equal in other regions. We suggest that regional analysis is very important for policy making as world is global village. We recommend that policies should not be same in all regions of the world for combating terrorism and have to alter region by region according to structural differences. Supervisor:- Dr Abdul Jalil