The rising support for radical parties in Europe has triggered a new interest in the political sociology of voting and how voters with socio-economic insecurity are moving away from establishment politics. In this article, we apply Standing’s concept of ‘precarity’ to capture insecurity among ordinary voters and thereby expand the individual socio-economic explanations behind the vote for radical populist right (RPR) and radical left (RL) parties. We develop a multidimensional measure of precarity to capture subjective labour market insecurity in its different manifestations. The article examines the influence of precarity on voting in two countries – France and the Netherlands – that, in the 2017 elections, saw the culmination of a decline in support for establishment parties and a rise in support for both RPR and RL parties. We use panels of voters collected during these elections through online Voting Advice Applications, weighted against national census benchmarks. We identify and assess the role of two dimensions of precarity: ‘precarity of tenure’ and ‘precarity at work’. We find that in both France and the Netherlands precarity is, overall, negatively correlated with voting for established parties and positively correlated with voting for RPR and RL parties. Furthermore, our investigation shows that ‘precarity at work’ is more significant in explaining voting support than the more widely investigated ‘precarity of tenure’. Our results stress the importance of assessing how subjective work insecurity explains voting and support for RPR and RL parties.