Chloride-induced depassivation of iron passive film in 13.5 pH NaOH solution was studied using Reactive Force Field Molecular Dynamics (ReaxFF-MD). The study involved the simulation of the passive oxide film formed in chloride-free 13.5 pH NaOH solution and the effect of incremental chloride addition to the solution on the oxide film. The interactions of chloride with the oxide film and the changes in the oxide film structure were investigated by monitoring different species, charge distributions, and the pair distribution functions over time. The relationship between different surface termination of the passive film (i.e., O-terminated surface vs. Fe-terminated surface) and chloride interactions was also studied. The results of the investigation were linked to existing depassivation models (e.g, the ion exchange model and the point defect model) and to a parallel Density Functional Theory (DFT) investigation of iron oxide and chloride interactions in water.