Per- and polyfluoroalkyl substances are persistent environmental contaminants increasingly implicated in neurotoxicity. Establishing causality and mechanisms relevant to Alzheimer’s disease, Parkinson’s disease, and multiple sclerosis requires human-relevant systems that capture exposure, barrier function, and brain circuitry. We review advanced cellular platforms—iPSC-derived neuronal and glial cultures, cerebral and midbrain organoids, and chip-based microphysiological systems—that model disease-relevant phenotypes (Aβ/tau pathology, dopaminergic vulnerability, myelination defects) under controlled PFAS exposures and defined genetic risk backgrounds. Modular, fluidically coupled BBB-on-chip → brain-organoid microphysiological systems have been reported, enabling chronic, low-dose PFAS perfusion under physiological shear, real-time barrier integrity readouts such as transepithelial/transendothelial electrical resistance (TEER), quantification of PFAS partitioning and translocation, and downstream neuronal–glial responses assessed by electrophysiology and multi-omics. Across platforms, convergent PFAS-responsive processes emerge—mitochondrial dysfunction and oxidative stress, lipid/ceramide dysregulation, neuroinflammatory signaling, and synaptic/network impairments—providing a mechanistic scaffold for biomarker discovery and gene–environment interrogation with isogenic lines. We outline principles for exposure design (environmentally relevant ranges, longitudinal paradigms), multimodal endpoints (omics, electrophysiology, imaging), and cross-lab standardization to improve comparability. Together, these models advance the quantitative evaluation of PFAS neurotoxicity and support translation into risk assessment and therapeutic strategies.