Plastics have become an inseparable part of modern life as a consequence of their versatility, low cost, durability, and lightweight. In this study, the presence of microplastics (MPs) in the stomachs and digestive tracts of 243 individuals of leaping mullet (Chelon saliens (Risso, 1810)), red mullet (Mullus barbatus barbatus Linnaeus, 1758), surmullet (Mullus surmuletus Linnaeus, 1758), Mediterranean horse mackerel (Trachurus mediterraneus (Steindachner, 1868)), and sand steenbras (Lithognathus mormyrus (Linnaeus, 1758)), collected along the Marmara, Aegean, and Mediterranean coasts of Turkey was examined microscopically and through μ-Raman analysis. A total of 283 MP particles were extracted. Among the examined species, the average MP concentration was 1.1 MP per fish (MPs fish–1). The number of MPs detected was 2.5 MPs fish–1 for leaping mullet, 1.1 MPs fish–1 for red mullet, 0.6 MPs fish–1 for sand steenbras, and 0.4 MPs fish–1 for Mediterranean horse mackerel and surmullet. The size of the MPs ranged from 0.028 to 4.909 mm. To determine the polymer types of the MPs, a μ-Raman analysis was conducted. The most frequently detected polymers were polypropylene (26%), polyethylene (21.9%), polyethylene terephthalate/polyester (8.2%), and cellulose (7.5%). The results of this study showed that MP pollution represents an emerging threat to the fish of Turkish marine waters.