["European Journal of Education, Volume 61, Issue 3, September 2026. ", "\nABSTRACT\nDigitally mediated assessment (DMRA) has become a central feature of contemporary higher education, particularly as institutions seek to evaluate key 21st‐century competences such as reading in technology‐rich environments. Grounded in Social Cognitive Theory, this mixed‐methods study investigates Vietnamese EFL undergraduates' attitudes toward DMRA, with specific attention to differences between more and less literacy‐advantaged students. A sequential explanatory design was employed. Quantitative data were collected from 562 undergraduates across two universities using a validated questionnaire, followed by semi‐structured interviews with eight participants. Statistical analyses included group comparisons and correlational examination of attitude dimensions, while qualitative thematic analysis was used to interpret underlying mechanisms. The findings reveal a differentiated attitudinal pattern. More literacy‐advantaged students expressed stronger cognitive endorsement of DMRA, whereas less literacy‐advantaged students reported more positive affective responses. However, behavioural engagement did not differ significantly between groups, indicating an attitude–behaviour decoupling in digitally mediated assessment contexts. Correlational results further suggest that affective responses were more closely associated with engagement than cognitive evaluations. Qualitative insights highlight the mediating role of trust in grading, technical reliability, platform interface, and institutional support in shaping sustained engagement. This study advances understanding of digitally mediated reading assessment by demonstrating that while attitudes diverge across literacy backgrounds, engagement converges under institutional assessment conditions. The findings underscore the importance of designing DMRA systems that prioritize usability, transparency and feedback trust to ensure equitable assessment of reading as a critical 21st‐century competence.\n"]