Despite the large number of working-class students having to work while attending schools, their work experience and the potential of class solidarity have been largely unaddressed. By bringing in a social psychological perspective, this article revives the sociological debates of working-class solidarity and challenges the defeatist view of solidarity since the neoliberal turn of the global economy. This article comprises two studies. In Study 1, a "working-class solidarity measure" (WCSM) was developed through interviews, followed by factor-analysis of a vocational school sample in China (n = 509). In Study 2, we validated the factor structure of the WCSM and adopted structural equation modelling to show that prosocial behaviour positively predicted solidarity among vocational school students (n = 2534). Contrary to the understanding that the working-class is divisive and fragmentary, our work shows that working-class solidarity can be built and consolidated through layers of prosocial behaviours by students with work experience.