A systematic review of 73 studies published between 2010 and 2023 found that microplastics are widely distributed in the world's oceans, with concentrations ranging from 0.002 to 62.50 items/m³, and an overall mean of 2.76 items/m³. The Atlantic Ocean had the highest mean concentration (4.98 items/m³), while the Southern Ocean had the lowest (0.04 items/m³). Microplastics were predominantly found in fragments, fibres, and films, with black and blue being the most common colors. Polymers such as polyethylene terephthalate (PET), polypropylene (PP), and polystyrene (PS) were the most frequently identified. The study highlights the need for standardized sampling, separation, and identification methods to improve data comparability and inform effective mitigation strategies for marine plastic pollution. The findings emphasize the importance of addressing microplastic pollution to protect marine ecosystems and human health.A systematic review of 73 studies published between 2010 and 2023 found that microplastics are widely distributed in the world's oceans, with concentrations ranging from 0.002 to 62.50 items/m³, and an overall mean of 2.76 items/m³. The Atlantic Ocean had the highest mean concentration (4.98 items/m³), while the Southern Ocean had the lowest (0.04 items/m³). Microplastics were predominantly found in fragments, fibres, and films, with black and blue being the most common colors. Polymers such as polyethylene terephthalate (PET), polypropylene (PP), and polystyrene (PS) were the most frequently identified. The study highlights the need for standardized sampling, separation, and identification methods to improve data comparability and inform effective mitigation strategies for marine plastic pollution. The findings emphasize the importance of addressing microplastic pollution to protect marine ecosystems and human health.