Background: Affordable interventions to improve metabolic control of Type 2-Diabetes Mellitus are increasingly necessary. Aim: To review systematically the existing literature on the effects of psychological interventions on Type-2 Diabetes Mellitus compensation. Material and Methods: We performed a systematic literature review and meta-analysis on the effectiveness of psychological interventions implemented for Type-2 Diabetes Mellitus patients. Research included the following electronic databases: PubMed, Bireme, Web of Science, SciELO, Embase, EBSCOhost, SCOPUS, Psychology Database. Results: Most studies showed a decrease in the level of glycated hemoglobin after interventions, which applied different initiatives complementary to standard medical treatment. Mainly, these interventions encompassed training for self-monitoring and control of diabetes based on cognitive behavioral psychology, counseling, self-assessment and physical-spiritual work based on transpersonal psychology. Conclusions: Psychological tools could be an adjunct to the standard medical treatment for patients with Type-2 Diabetes Mellitus, reducing glycated hemoglobin levels and improving self-regulation, disease awareness and adherence from the self-efficacy perception perspective.