The article examines the connection between protests and elections in an authoritarian context. Using the concept of mobilization momentum, the authors attempt to find out whether intensive and massive collective actions on the eve of elections can affect electoral mobilization and support for the “party in power”, and if so, in what direction. Based on the modern literature on this topic, the authors identify two alternative models of the possible electoral effect of the mobilization momentum. According to the first model, by breaking through the information blockade and signaling to citizens about the widespread dissatisfaction with the authorities’ policies, intense mass protests contribute to an increase in voters’ turnout and a decrease in support for pro-government forces. According to the second model, such protests may easily increase the electoral performance of the “party in power,” since they often lead to the mobilization of an electorate that is loyal to the ruling circles. The authors test these hypotheses against the evidence from the 2011— 2016 parliamentary electoral cycle in Russia using methods of standard multiple linear regression, difference-in-differences and synthetic control. The results are mixed. It appears that the mobilization momentum has a weak electoral effect or even a positive effect on the performance of the “party in power,” but its influence may depend on threshold values: in the most protesting cities, support for the United Russia turns out to be lower than it would be in the absence of the mobilization momentum. At the same time, the findings convincingly demonstrate that the evidence and data from the Russian context, combined with modern methods of analysis, opens up an excellent opportunity for research at the intersection of the spheres of political participation and electoral politics.