Purpose <p>Social constraints represent negative social responses to the disclosure of cancer-related experiences, which can influence how individuals communicate about and appraise their illness and relationships, thereby affecting their adaptation to cancer. Adults with cancer and their caregivers experience social constraints. Individual interventional studies yielded inconsistent results on mitigating social constraints. This systematic review aimed to synthesise the effectiveness of existing interventions targeting social constraints for adults with cancer and their caregivers.</p> Method <p>RCTs from eight English language databases and one Chinese language database were searched from inception to 8 March 2024. The updated Cochrane risk-of-bias tool was used to assess the quality of the included RCTs. Findings were then summarised in narrative form.</p> Results <p>Seven studies with 1,166 adults with cancer and 106 caregivers were included. Intervention content included expressive writing, cognitive behavioural and emotion-focused therapy, psycho-educational written and audio/visual content and hula dance. Expressive writing was the predominant intervention. Four studies (57.14%) reported results on social constraints. Mixed results were observed on social constraints in adults with cancer, with one study (14.29%) reporting significant and positive results, two studies (28.57%) reporting nonsignificant positive results and one study reporting negative but non-significant results. Only one study (14.29%) examined the effectiveness of the intervention on caregivers with non-significant results.</p> Conclusions <p>Findings indicated that interventions in the current review have limited effects on social constraints among adults with cancer. The most common intervention component was expressive writing, accompanied with cognitive and/or psychological support in one study. Insufficient evidence for caregivers was observed, as only one study focused on caregivers, yielding a non-significant result. Future research is encouraged for adults with cancer and their caregivers, employing rigorous study designs and long-term follow-up periods.</p>