The article analyzes the impact of the Arab Spring on destabilization processes in Eastern Europe. The authors show how the success of the Arab revolutions influenced the rise of protest activity in Eastern Europe in 2011. The similarities of the protests in Eastern Europe with the protests of the Arab Spring period are demonstrated. We also analyze ways of borrowing patterns of destabilization. The wave of protest activity after 2011 is compared with the previous wave of protest activity initiated by the global financial-economic crises of 2008–2009. In addition to the external factor of the Arab Spring, the article examines the internal factors of the protest activity of the second wave of the economic crisis associated with the economic crises in Portugal, Italy, Spain, and Greece. The authors define the most typical forms of destabilization for Eastern Europe: anti-government demonstrations, riots, terrorist actions, and guerrilla warfare. The contribution of the Ukrainian Revolution in 2014 to the dynamics of the most violent forms of protest in Eastern Europe is also analyzed. In explaining the special case of Ukraine which breaks with the general trend of Eastern Europe, the authors show that Ukraine experienced a transition from less-violent forms of destabilization (anti-government demonstrations and riots) to more violent ones (guerrilla warfare and terrorist attacks) in 2013–2014. The reasons for the growth of terrorist activity and guerrilla warfare as well as the role of the war in Donbass are discussed. It is shown that though the case of Ukraine is unique for Eastern Europe in the period under study, it has many parallels on a global scale.