This thesis asks how Russia’s justifications for vetoing resolutions on Syria were shaped by Russia’s national interests. Employing a qualitative holistic case study method, the study intends to analyse different aspects of the problem. These aspects are the economic interests and the interest in maximising power that Russia has in Syria, in connection to the justifications that Russia gives in the Security Council. It includes an analysis of the interests of Russia, which are defined by economic interests and the advancement of power in the international system in this study. These aspects are analysed from a realist theoretical perspective. The findings are that certain justifications of Russia in the Security Council for vetoing resolutions on Syria can be connected to specific interests of Russia in Syria. The arms trade with the Syrian authorities and the maximisation of power and influence for Russia are argued to be the main national interests driving the key arguments the Russian justifications of vetoes in the Security Council regarding the Syrian civil war.