<p>Collective actions and protests are often considered the most influential means to achieve changes in current systems. Therefore, achieving high support for such actions is essential. However, factors such as system justification or the aim of the actions might reduce public support for collective actions. In two studies, we examined the effects of dispositional and situational system justification on protest support, using between-subjects design with scenarios describing protests aimed at legislation on strikes (Study 1) and working time (Study 2). In Study 1 (<i>N</i> = 203), we found that people high in system justification and those who read a scenario describing a protest challenging the current system compared to a protest supporting the current system reported less support for the described protest. In Study 2 (<i>N</i> = 797) we were able to replicate these results using a different protest topic and a larger sample. Thus, system justification can influence the support for protests, but further factors, such as the protest topic, should be considered by both protest organizers and researchers.</p>