Abstract: Background Families experience high levels of stress during a loved one’s critical illness. Objective To provide an overview of current evidence on the use of journal writing as a coping mechanism for family members during a loved one’s critical illness in a neonatal, pediatric, or adult intensive care unit. Methods Five databases (MEDLINE, PsycINFO, CINAHL, APA PsycArticles, and Health Source: Nursing/Academic Edition) were searched to identify studies examining the benefits of journal writing for family members of critically ill patients. Eight eligible studies reported data from 426 relatives of critically ill patients. Results Regarding quality assessment, the quantitative studies met 73.1% of relevant quality criteria, whereas qualitative studies met 81.3%. Mixed-methods studies met 82.4% of quantitative and 55% of qualitative criteria. Various key themes were identified: communication and understanding, connection to the patient, emotional expression, creating something meaningful, and the importance of pictures and staff entries. Overall, writing in a diary seems to be beneficial for reducing psychological distress and posttraumatic stress disorder, but none of the studies found that it significantly decreased anxiety or depression. Conclusions The findings of this review suggest that having family members of critically ill patients write in a diary is a simple and cost-effective intervention that may improve their psychological outcomes. Critical care nurses are in a position to educate families about the potential benefits of writing in a diary. Future research would be valuable regarding the benefits of using a diary and an optimal approach for doing so in this population.