Informal caregiving is associated with mental disorders and reduced quality of life. The aim of this systematic review was to summarize the results of methodologically high-quality intervention studies on the effectiveness of non-pharmacological interventions on patient-relevant outcomes for family caregivers in Germany. We searched three large scientific literature databases for intervention studies with a control group and a low or moderate risk of bias on the effectiveness of non-pharmacological interventions for family caregivers in Germany. Among 4,376 publications reviewed, 10 intervention studies with good methodological quality were identified. These investigated multi-component interventions or cognitive behavioral therapy for family caregivers of people with dementia (8 studies), stroke (1 study) and with general care dependency (1 study). The control groups received information material as a minimal intervention or usual standard care. Meta-analyses showed a statistically significant slight reduction in depressive symptoms 3-6 months after the start of the study as a result of cognitive behavioral therapy (standardized mean difference -0.27; 95% confidence interval -0.44 - -0.10), but this no longer reached statistical significance after 9-12 months (-0.21; -0.51 - 0.09). Multi-component interventions showed no changes in depressive symptoms either after 3-6 or after 9-12 months (-0.18; -0.40 - 0.03 and -0.14; -0.47 - 0.14, respectively). In contrast, the mental component of quality of life of family caregivers improved statistically significantly in the multi-component intervention groups compared to the control groups: slightly after 3-6 months (0.28; 0.01 - 0.56) and moderately after 9-12 months (0.45; 0.09 - 0.82). The interventions had no effect on the physical component of quality of life. The reduction of depressive symptoms by behavioral therapy interventions for family caregivers appears to be only slight and not sustainable. The mental component of quality of life of people affected may be improved in the longer term by multi-component interventions. Current scientifically examined interventions for informal caregivers do not appear to have a sufficient and sustainable effect. Greater effects could possibly be achieved through more elaborate behavioral approaches, but also structural preventive measures.