Trauma-informed care (TIC) psychoeducational group-based interventions for foster carers and adoptive parents are growing, but evidence about their effects have not been integrated. A narrative review was undertaken of studies that evaluated the effects of these interventions. It found that they appear to increase carers' capacity to provide children with TIC and reduce child trauma-related difficulties. Three core components - psychoeducation, reflective engagement and skills building - were identified as helping to explain how the interventions work. However, the evidence is weak due to the mixed findings, diverse research designs, varied measures and methodological deficiencies, so results should be interpreted with caution. This highlights the urgent need for more rigorous research. Implications for practice, policy and research are discussed.