The purpose of this quantitative cross-sectional study was to obtain a more accurate diagnosis of the factors that incite terrorism through examining the extent to which independent variables (the Group Grievance Index (GGI), the Legitimate State Index (LSI), and the External Intervention Index (EII)) can predict the dependent variable (the level of global terrorism (GTI)) for the period between 2006-2017. The study included data from the 162 member states of the United Nations, covering 99.7% of the world's population. Game theory and the political process theory provided the theoretical frameworks for the study. Multinomial logistic regression analysis was used to assess the effect of the interaction on the relation between GGI, SLI, EII, and GTI. The results of the study showed that the relationship between the level of terrorism and the independent variables varies according to the level of terrorism. Interaction between GGI, SLI, and EII was negatively associated with GTI in countries with low GTI risk with an adjusted odds ratio 0.99, but in the countries with a medium and high level of GTI, the relationship was positive, and the adjusted odds ratio was respectively 1.01 and 1.02. The findings benefit international and national security decision-makers by identifying the nature of the relationship between terrorism and the factors affecting it. As well, the importance of considering the interaction between variables that affect terrorism. The results of the study may serve to bring social change within government cultures in the third world when dealing with minorities and grievance groups. Furthermore, it may motivate third world nations to achieve legitimate representation within all social strata and push the international community to reduce interference in the affairs of other sovereign nations.