Microplastic pollution is one of the emerging and challenging environmental issues that we face today. Freshwaters, sediment, fauna, flora and air are increasingly reported to be contaminated with tiny plastic fragments and fibres, particles smaller than 5mm. These microplastics often originate from land-based sources such as direct littering, surface water run-off, household wastewater discharges and particularly from sewage treatment plants. The microplastic in the environment raises concerns for the associated ecosystem and human health impacts. Rapid urbanisation, economic growth and changes in production and consumption patterns have contributed to the growing problem of microplastics (and macroplastics), not only at national level but also at the regional level, especially in ASEAN region comprising 10 member states of the Association of Southeast Asian Nations. In addition, the takeaway food culture, ‘growing e-commerce’ and ‘sachet economy’ are seen in many ASEAN countries, leading to an increase in plastic use. Consumers change their preferences from traditional fresh foods to packaged foods, and at the same time, shopping on digital platforms is on the rise. Consequently, this convenience and versatility have led to an increase in plastic waste, and mismanaged plastic waste became an emerging environmental problem. This study provides a comprehensive review of the current state of knowledge on the occurrence, ingestion and impacts of microplastic pollution on ecosystems and human health. The case study was conducted in the Philippines to identify the occurrences (characterized by size, morphology, color, polymer types and volume of discharges) and potential ecosystem and human health impacts caused by riverine microplastic pollution, originated from various sources, such as domestic and industrial wastewater discharges, direct littering, surface water run-off, and sewage treatment plants. They are a major source of microplastic pollution in the Philippines. The results from this study have become scientific based-evidences for proposing various mitigation measures, such as (i) standardization of microplastic monitoring and measurement methods; (ii) construction of centralized Material Recovery Facilities (MRFs); (iii) improvement of knowledge, skills and technical capacity of relevant policy and decision makers at both central and local level regarding both macro- and microplastics pollution control; (iv) raising producer and consumer awareness and helping them to understand the adverse effects on both macro- and microplastic pollution on ecosystems and human health; (v) introducing “Design for Recycling” standard for plastics application to ensure that all products in the markets are truly recyclable; (vi) amend the existing laws, policies and regulations to integrate plastics and microplastics management; and (vii) strict plastic bans and regulations enforcement.