The present research focuses on populism as a bottom-up phenomenon that emerges from shared perceptions of relative deprivation. We predict that by serving as a shared ideological basis, populist attitudes can mobilize leaderless anti-government protest across ideological boundaries. We test this prediction in the context of the French Yellow Vests movement. Using a sample of French citizens (N = 562), we compare the effects of different indicators of relative deprivation on Yellow Vest protest participation and the extent to which populist attitudes account for these relationships. Results indicate that protests were fuelled by indicators of relative deprivation at the individual and group levels. Populist attitudes were best predicted by vertical comparisons between “the people” and “the elite” and fully accounted for the relationship between this type of group relative deprivation and protesting. Conversely, populist attitudes only partially accounted for the relationships between protesting and traditional measures of relative deprivation that either contrast natives with immigrants or individuals with fellow citizens. The findings strengthen the understanding of populism as a “thin centred” belief set that can unite and mobilize those who feel unfairly disadvantaged compared to a socio-political elite.