Our modern era is witnessing an increased prevalence of neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, Huntington's disease and brain tumors. This is accompanied by an increased production of nanoparticles (NPs) and the subsequent release of NPs in the environment shared by humans. NPs are extremely small molecules measuring about 100 nm in diameter. Due to minuscule size, NPs have the potential to penetrate human body through various pathways and eventually cross the blood-brain barrier to potentially cause neurotoxicity, neuroinflammation and neurodegeneration of the central nervous system. Until recently, the mechanisms by which NPs cause neuroinflammation and neurodegeneration were unknown. However, recent in vivo, ex vivo and in vitro studies have significantly advanced our understanding of the mechanisms by which NPs may cause neurotoxicity and neurodegeneration. In light of this understanding, various pathways have been identified as the basic mechanisms by which NPs cause damage in the brain. The goal of this review is to summarize new mechanistic findings and different pathways of NP-induced neurotoxicity. Better knowledge of such pathways can lead researchers to devise effective therapeutic strategies for neuroprotection against nanoparticles.