While much research has been devoted to the effects of inequality on political participation, little attention has been paid to how different kinds of subjective perceptions of social inequality affect citizens’ political behaviour. This is important since these perceptions shape the message that reaches political decision-makers when addressing concerns over social inequalities. This article differentiates between sociotropic and egocentric perceptions of social inequality and explores to what extent individuals’ perceptions of such inequality affect engagement in institutionalized and non-institutionalized political participation between elections. Engagement was evaluated with a survey among a segment of the Finnish population (n = 1673). Our results indicate that citizens with sociotropic concerns are more likely to get involved in both institutionalized and non-institutionalized forms of political participation, whereas egocentric perceptions have less of an impact. Furthermore, the associations are moderated by left–right ideology: sociotropic concerns are more strongly expressed among left-wing voters, whereas right-wingers are more likely to be propelled to action by egocentric concerns.