Introduction: Health and social care systems are constantly undergoing major reforms to meet the rising demands of an increasing proportion of older patients, with many such reforms aiming to improve integration and coordination. The aim of this systematic review was to synthesize the evidence on inter-organizational coordination interventions between hospitals and outpatient (health- and social care) providers for older patients with complex needs during- and after hospital discharge.Methods: A systematic search of four databases was performed to identify interventions of inter-organizational coordination at hospital discharge for older patients with complex needs. The retrieved literature was analyzed using a narrative synthesis.Results: Twelve studies were included (seven randomized controlled trials and five non-randomized intervention studies). The most common intervention components were; needs assessments, dedicated care coordinators and multi-professional teams. Findings show that inter-organizational coordination could decrease- or even increase readmission rates, with similar findings for hospital length of stay and mortality. Furthermore, inter-organizational coordination seemed to have a positive impact on quality of life and activities of daily living.Conclusion: Inter-organizational coordination could potentially reduce health-care utilization and improve quality of life for older patients with complex needs. However, the findings remain uncertain and further research is warranted.