Abstract: Microplastics have increasingly been recognized as a global pollutant due to their pervasive distribution and potential adverse impacts on marine ecosystems. Microplastics (MPs) were collected from surface sediments at five sites in the Gulf of Gemlik using density separation. The isolated MPs were subsequently identified and characterized with a stereomicroscope and fluore scence microscope. This study provides the first comprehensiveassessment of microplastic pollution in the sediments of the Gulf of Gemlik, focusing on their abundance, spatial distribution, and potential ecological risks. The concentration of the MPs ranged from 2,200 to 6,400 items per kilogram of dry weight across the study sites. Fibers were the dominant shape type (58.4%), while black was the mostprevalent color (26%). According to the ecological risk assessment, the sediments were classified as moderately to considerably contaminated with MPs. These findings contribute new insights in the occurrence and characteristics of microplastics in the surface sediments of the Gulf of Gemlik and establish a foundation for future research and management strategies aimed at mitigating microplastic pollution.