In this article, we examine the extent to which typical workers act in solidarity with atypical workers. We collected unique survey data from United Auto Workers striking against General Motors in 2019 during the strike and after the ratification vote. Although solidarity was generally high, we do find that typical workers with longer tenure exhibit less solidarity with atypical workers and that they are more prone to be on strike due to material reasons. In the second survey, after workers had voted on the proposed contract, we find that typical workers were more prone to vote yes to the agreement for self-interested, material reasons and that solidarity with atypical workers had a significant, negative effect on the probability of voting yes to the agreement. Our findings support notions that insiders strike and vote according to self-interests. We discuss these findings in light of the insider/outsider, dualization and union strategy literature.