Abstract: To enable risk characterization of perfluorooctane sulfonic acid in extended chronic and multi-generational exposures, we assessed PFOS bioconcentration in zebrafish exposed continuously to environmentally-relevant PFOS concentrations through 180 days postfertilization in parental and first filial generation fish. Exposures included five replicate tanks per treatment where whole-body PFOS concentrations were measured. Perfluorooctane sulfonic acid accumulation reached an apparent steady state at ≤ 14 dpf where whole-body wet-weight concentrations remained constant through 180 dpf in the P and F1 generations. The median bioconcentration factor of 934 L/kg was observed for all PFOS exposures with a range from 255 to 2,136 L/kg which varied with PFOS exposure concentration and sex of adult fish. Maternal transfer of PFOS was observed from P females to F1 eggs where maternal whole-body and egg PFOS burdens were equivalent, suggesting PFOS transfer to eggs was not a depuration pathway. Finally, a toxicokinetic model was developed that reliably reproduced PFOS whole-body burdens across all exposure durations spanning the P and F1 generations, providing a tool for PFOS bioaccumulation predictions relevant for risk assessment of acute, chronic, and multi-generational exposures.