Patient activation has been recognised as a reliable driver of self-management decision-making. This systematic review and meta-Analysis examines existing evidence on whether embedding patient activation within Type 2 diabetes mellitus (T2DM) self-management programs can improve patient outcomes. This review has included 10 randomised controlled trials (RCTs) conducted between 2004 and 2019 retrieved from well-known databases such as MEDLINE, PubMed, CINAHL Plus, Scopus, ProQuest and ScienceDirect. The eligible RCTs were excluded if they scored low according to Cochrane Collaboration's 'risk of bias' criteria. Random-effects meta-Analyses showed that there were no significance changes in haemoglobin A1C (HbA1c), body mass index (BMI) and patient activation measure (PAM) between intervention and control groups after the intervention; however, the systematic review findings indicated that an improved patient activation level led to significant improvements in T2DM self-management and clinical outcomes including HbA1c level. Studies with a longer follow-up period conducted in community settings and delivered by peer coaches were more likely to lead to significant improvement in both patient activation levels and T2DM self-management and clinical outcomes. This review concludes that patient activation can be used as a reliable tool for improving T2DM self-management and clinical outcomes.