Stress is known to be a risk factor for deficits in working memory creating profound cognitive disturbances resulting in lingering impairments and losses in social and occupational functioning. Although a body of research has identified mindfulness as a potential means of mitigating deficits in working memory, there is a paucity of studies on the association between mindfulness and deficits in working memory among those who have experienced COVID-19 traumatic stress. This exploratory cross-sectional study sought to examine the mitigating effect of mindfulness on COVID-19 stress impacting working memory. The sample included 484 college students in Israel and the USA. Correlation and multiple regression analyses indicated that COVID-19 stress had a modest, inverse association with both a self-report and task-based indicator of working memory. In separate models predicting the different operationalizations of working memory, results revealed different effects for Israeli and USA students. Mindfulness was significantly associated with task-based but not self-reported working memory. The results offered evidence for a small but significant effect of mindfulness as moderating the impact of COVID-19 stress on working memory deficits. This exploratory, cross-sectional study, used a convenience sample limiting the generalizability and its ability to test causal effects, calling for replication.