Benefit finding is a concept that represents finding positive changes or benefits through difficult experiences. To map the currently available studies on benefit finding and growth among family caregivers of individuals with mental illness, we conducted a scoping review based on methodological frameworks. A systematic search for studies published in English was conducted using MEDLINE, PsycINFO, PsycARTICLES, CINAHL, and PTSDpubs from inception to August 2023. After screening, 21 articles were included in the review. Of these, 11 studies were cross-sectional studies, 7 were qualitative studies, 2 were mixed-methods studies, and a randomized controlled trial (RCT). Family caregivers experienced various positive psychological changes, such as becoming compassionate/tolerant and resilient, stronger family bonds, change in perspective on life and hope, acquisition of knowledge and coping strategies, and leveraging their experiences and appreciation by others, following various struggles and negative changes. Some indicators of benefit finding and growth, such as positive personal traits, positive reappraisal, good relationships with patients, and social support, were also revealed. The quality assessment demonstrated an acceptable level of quality in most studies, with a few outliers. Future longitudinal studies would reveal the mechanism of benefit finding and growth among family caregivers of individuals with mental illness.