COVID-19 has caused psychological problems in all age groups since it emerged from the first day. One of the most important groups has been affected negatively during the COVID-19 pandemic process are university students. One of the negative situations caused by the pandemic process in university students is student stress caused by COVID-19. To assess stress situations in Italian culture, the COVID-19 student stress scale (CSS-S) has been developed. In this context, the aim of this study was to adapt the CSS-S into Turkish. Another aim of the study was to investigate the direct and indirect relationships of COVID-19 student stress with school burnout, depression and subjective well-being. The participants of the study were 485 Turkish university students. The values obtained with the confirmatory factor analysis revealed that the factor structure of CSS-S is satisfying (X[superscript 2]/df = 2.99, AGFI = 0.95, TLI = 0.93, CFI = 0.96, IFI = 0.96, REMSEA = 0.06, SRMR = 0.04). Moreover, it was found that school burnout has a mediating role in the relationship between COVID-19 student stress and depression and subjective well-being (X structure of CSS-S is satisfying/df = 2.41, AGFI = 0.87, TLI = 0.91, CFI = 0.91, IFI = 0.91, REMSEA = 0.05, SRMR = 0.05). These findings imply that psychosocial intervention studies to reduce COVID-19 student stress can reduce students' school burnout and depression. It also implies that these psychosocial intervention studies can have a positive impact on students' subjective well-being.