This paper reports the findings of an updated systematic review on the evidence for the effectiveness of mindfulness-based interventions (MBIs) on social workers’ mental health. We addressed two research questions: (RQ1): What are the effects of MBI on social workers’ stress, burnout, mental wellbeing, coping, and resilience? (RQ2): What is the effective structure of MBIs in relation to these outcomes? The review searched seven databases for peer-reviewed papers published from 2014 to 2022. Most of the nine studies meeting inclusion criteria had used non-randomized control methods. All reported positive effects of one type of MBI in at least one of the outcomes. However, not all the improvements were statistically significant. The strongest effects reported were for stress and burnout. Several of the studies had very few social worker participants, and few studies reported long-term impacts or cost-effectiveness. Mindfulness may have positive effects on social workers’ state of mind, health, and professional outcomes. However, studies that enable us to draw conclusions about causality and evaluate the impact of a MBI on social workers are scarce; long-term impacts and cost-effectiveness are also under-studied.