This study presents a comprehensive assessment of microplastics in water, sediment, and fish species (Clarias gariepinus and Oreochromis niloticus) of the Ikpoba River. Water samples were collected using twenty-five-litre stainless steel buckets, sediment samples were obtained using a Van Veen grab sampler, and fish samples were collected using gill nets and hand nets respectively. Microplastics were extracted from water and sediment samples using a density separation method, employing a saturated sodium chloride solution. Fish samples were dissected, and the gastrointestinal tracts (GIT) were examined for the presence of microplastics. Attenuated Total Reflectance Fourier-Transform Infrared Spectroscopy (FTIR) was employed to confirm the polymer composition of select particles. The results indicate the widespread presence of microplastics in the Ikpoba rivers ecosystem with a high prevalence of polypropylene (PP), polystyrene (PS), and polyethylene (PE) in surface water and Polyethylene terephthalate (PET) and Polyvinyl chloride (PVC) in sediment samples. In fish samples, C. gariepinus accumulated the highest concentration of microplastics compared to O. niloticus. The polymer PE was highest in both fish species followed by PC. Most MP shapes identified in this study consist of fiber, film, foam, and fragments in water, sediment, and fish. Therefore, this study quantitatively demonstrates the presence of microplastic contamination in the Ikpoba River and thus raises significant concerns about the vulnerability of the local fish population to microplastic ingestion.