Despite the prohibition of organochlorine pesticides (OCPs) in Morocco since 1984, our study revealed a widespread presence of these chemicals in the muscles of three fish species from the Al Massira Reservoir. Average concentrations of OCPs varied among the species, with higher levels found in Sander lucioperca compared to Oreochromis niloticus and Cyprinus carpio. Specifically, the average concentrations of the sum of hexachlorocyclohexane isomers (ΣHCHs) were 1.46 ± 1.14 for Oreochromis niloticus, 2.05 ± 1.55 for Cyprinus carpio, and 3.38 ± 2.22 for Sander lucioperca. For the sum of aldrin and dieldrin isomers (ΣDrins), concentrations were 2.40 ± 2.18 for Oreochromis niloticus, 2.61 ± 2.41 for Cyprinus carpio, and 6.01 ± 3.97 for Sander lucioperca. The average concentrations of the sum of dichlorodiphenyltrichloroethane isomers (ΣDDT) were 1.83 ± 1.72, 2.57 ± 2.36, and 4.70 ± 4.65, respectively, for Oreochromis niloticus, Cyprinus carpio, and Sander lucioperca. Despite these findings, none of the samples exceeded the maximum residue limits (MRLs) set by the European Commission. Risk assessments for both cancer and non-cancer risks associated with consuming these fish indicating that there is no significant threat to public health. However, ongoing monitoring of aquatic ecosystems is essential to ensure food safety and to protect the well-being of local populations. Addressing global concerns about human exposure to persistent organic pollutants (POPs) requires coordinated efforts and continued vigilance.