Nanoparticles (NPs) are at the forefront as they are providing unprecedented solutions to obstacles and issues in treating neurodegenerative diseases. Due to their size, surface characteristics, and ability to be functionalized, these carriers can directly deliver therapeutics across what is considered one of the main barriers to central nervous system (CNS) treatment, the blood-brain barrier (BBB). Through nano-technology, anti-disease agents such as Alzheimer’s, Parkinson’s, and Huntington’s therapies become more bioavailable, specific in action, and with fewer side effects. The NPs serve as molecular carriers that facilitate transport across the BBB by receptor-mediated transcytosis or by disruption of the barrier with a view to properly delivering drugs to the neural tissues. Some of the therapeutic applications of nanotechnology also present the concept of molecular medicine since the NPs are designed to deliver drugs in accordance with specific biomolecule signals. Besides the therapeutic applications, NPs replace the traditional contrast media for magnetic resonance imaging (MRI) and positron emission tomography (PET) scans for better diagnosis as well as disease tracking in the early stages. In addition, their effects on solubility increase the therapeutic potential of earlier useless compounds, and the preservation of bioactive molecules from degradation increases the therapeutic capacity of medications. Neurodegenerative disorders are marked by oxidative stress and inflammation that contribute to the disease severity; thus, liposomes, dendrimers, and polymeric NPs encapsulate antioxidants and anti-inflammatory compounds, so they target the areas most affected by the disease. Such sophisticated systems minimize the extension of neuronal deterioration and enhance the lot of such patients. The “theranostic” NPs allow for continuous diagnosis and treatment by containing both diagnostic and therapeutic features. These have created unprecedented opportunities to meet the unmet needs in CNS disorders and may revolutionize the evolution of managing neurodegenerative diseases and innovative neuroimaging procedures in the future.