Background: Individuals recovering from a suicide attempt may benefit from support provided by informal carers, that is, family members and other support persons, who may require support themselves. Aims: This systematic review aims to identify and synthesize available literature on the effectiveness of psychosocial interventions for this carer population. Method: A search of peer-reviewed literature in five databases was carried out. Studies using any design were eligible and results were synthesized using a narrative review. Results: Eight articles reporting on seven quantitative studies met the eligibility criteria. This included three studies on interventions designed specifically for informal carers and four studies on interventions designed for persons who have made a suicide attempt, and which involved their informal carers. Overall, informal carers were satisfied with support and psychosocial interventions they received. Interventions were related to some improvements in carers' mental health outcomes, lowered burden, and improved ability to provide care. There were mixed results regarding family functioning and quality of life. Limitations: No studies from lower- and middle-income countries were identified and the small number of heterogeneous studies precluded conducting a meta-analysis. Conclusion: Given the low number of studies and their overall poor quality, this review can only draw preliminary conclusions. More high-quality intervention studies are needed to formulate recommendations for effective psychosocial support for family members and other informal support persons after a suicide attempt.