Wars represent one of the most serious threats to the world order; It is considered a violation of international laws and norms, and humanitarian principles. From this point comes the study of the importance of the topic entitled (The Future of the Russian-Ukrainian war and the extent of its Reflection on the security of Eastern European countries after the year 2022). This study is based on reviewing future possibilities (scenarios) of war. The Russian-Ukrainian war, which was launched by the Russian government led by Russian President Vladimir Putin in February 2022, is still ongoing at the time of writing this research. This chapter includes three possibilities (scenarios). The first possibility deals with the development of the war to dangerous levels, and this possibility is unlikely. Because both sides of the conflict (the West and Russia) possess nuclear deterrence. While the second possibility deals with the continuation of the war, this is also unlikely because history has proven that every war has an end, even if it is somewhat long, but it will inevitably end. The third possibility deals with a solution to end the war, which is likely and is expected to satisfy Russia because Russia will not accept withdrawal without compensation or keeping the areas controlled by Russia and to which they are annexed. These are the expected possibilities (scenarios) in the Russian-Ukrainian war.