: Quantum dots (QDs) are nanoparticles (NPs) with electronic and optical properties such as emitting bright light and fluorescence. They also carry specific characters such as photostability, high quantum yield, high emission, and size-turnable. Nowadays, a great interest is given to the extensive use of theranostic-NPs for sensing and imaging, as well as drug delivery. Moreover, QDs may yield great potential for the diagnosis and treatment of various central nervous system (CNS) diseases (e.g., Parkinson’s disease, Alzheimer’s disease, and multiple sclerosis). The blood-brain barrier (BBB) protects the brain tissue. Only certain small molecules like water and gases can cross BBB, whereas larger molecules enter via receptors, but many drugs are incapable of passing the barrier. A series of great advances have been achieved concerning using different NPs (e.g., QDs) to deliver drugs to the brain and CNS imaging. In this review, we discussed a wide variety of QDs along with their production, passive or active delivery of therapeutic agents for neurodegenerative diseases, and different image production.