Threats emerging from microplastic pollution in the marine environment have received much global attention. This review assessed sources, fate, and impacts of microplastics in marine ecosystems and identified gaps. Most studies document the ubiquity of microplastics and associated environmental effects. Effects include impacts to marine ecosystems, risks to biodiversity, and threats to human health. Microplastic leakage into marine ecosystems arises from plastic waste mismanagement and a lack of effective mitigative strategies. This review identified a scarcity of microplastics’ mitigation strategies from different stakeholders. Lack of community involvement in microplastic monitoring or ecosystem conservation exists due to limited existence of citizen science and stakeholder co-management initiatives. Although some management strategies exist for controlling effects of microplastics (often implemented by local and global environmental groups), a standardized management strategy to mitigate microplastics in coastal areas is urgently required. There is a need to review policy interventions aimed at plastic reduction in or near coastal ecosystems and evaluate their effectiveness. There is also a need to identify focal causes of microplastic pollution in the marine environment through further environmental research and governance approaches. These would extend to creating more effective policies as well as harmonized and extended efforts of educational campaigns and incentives for plastic waste reduction while mandating stringent penalties to help reduce microplastic leakage into the marine environment.