BACKGROUND: Psychosocial interventions may improve QoL in people with wider chronic pain conditions. However, the evidence requires refining for application to EDS/JHMS. This systematic review aimed to identify, assess and synthesise the evidence of the effectiveness of psychosocial interventions concerning EDS/JHMS. EBSCO, OpenGrey, Cochrane, Prospero, Researchgate and BPS Wiley online were searched for papers published approximately 2000-2024 for studies in which (1) Participants diagnosed with EDS/JHMS. (2) Quantitative or mixed methods. (3) Assessed a Psychosocial intervention to a (4) quality of life outcome. (5) in English. EPHPP quality assessment tool was used to assess the quality and risk of bias. MAIN TEXT: The study identified six studies, including 343 participants aged 13-69 (F = 248, M = 8), of unknown ethnicity. Five studies were cohort and one non-randomised controlled trial. Key methodological flaws included no reported effect size and no control group. With quality assessed as low (5) or moderate (1), there was weak evidence that psychosocial interventions containing mindfulness and CBT resulted in a general improvement in QoL compared to no intervention. CONCLUSIONS: Findings from this review indicate the potential of mindfulness and CBT in improving QOL in EDS/JHMS and, in some studies, pain and fatigue. However, existing research is at high risk of bias, has low methodological quality, and is predominately focused on female patients. Future research should adopt methodologically robust approaches such as RCTs and more inclusive samples and consider co-production.