Educational assessment is an ever-present component of any formal learning environment that has critical consequences for students.  Despite this relevance, there is a gap in knowledge regarding one of its foundations --namely, assessment fairness.  In particular, social class-based fairness of classroom assessment practices has been understudied at the higher education level.  We know little about how fairness is threatened due to class-related issues, and which strategies are deployed, by instructors and college students, to counter those threats.  Also, a gap in empirical knowledge exists regarding how working-class students resist those potentially unfair assessment practices. Therefore, the purpose of this multiple-case study was to explore how social class-based fairness was enacted in classroom assessment, and how working-class college students reacted when confronted with unfairness.  Data collection took place at two different Chilean universities: one affluent and one non-affluent university, in which I interviewed thirty faculty members and working-class students, and analyzed course syllabi, examples of assessment instruments, and examples of written feedback.  Guided by a conceptual framework formed by three bodies of theories and research (fairness in educational assessment, social reproduction in education, and student resistance), I conducted qualitative analyses that uncovered the findings of this study. I found that important threats to class-based fairness were present in all the phases of the assessment cycle (i.e., assessment construction, examination, grading, and provision of feedback), at both the affluent and the non-affluent institutions (although the threats were more prevalent in the former than in the latter).  At the same time, I found that instructors and students deployed a wide array of strategies in order to counter those threats, but their effectiveness varied.  However, some of the class-based threats to fairness did not have strategies countering them, leading me to conclude that unfair classroom assessment practices make higher education harder for working-class students than for their more affluent peers. Finally, I found that working-class students engaged in actions aimed to resist the classroom assessment practices that they perceived to be unfair. They exhibited conformity, conformist resistance, and transformational resistance, and engaged in both subtle and more disruptive forms of resistance.  Important differences between students in the affluent and the non-affluent universities emerged, regarding their perspectives, actions, and forms of resistance.  This study offers a number of strategies that faculty members could adopt to achieve fairer assessment, as well as an array of situations that constitute threats to class-based fairness and which they should avoid.  This study also highlights areas of training and reflection (such as provision of quality feedback and self-reflection on class privilege and ingrained stereotypes toward working-class students) that university administrators should include in faculty development initiatives.