Parkinson’s disease (PD) is a chronic and progressive neurodegenerative disease that is characterized clinically by motor dysfunctions such as tremors, muscle rigidity, and bradykinesia. NAD+ plays a crucial role in cellular metabolism, DNA repair, and regulation of gene expression and is an indispensable factor for maintaining neuronal health. The decline of NAD+ levels in the brains of PD patients is associated with disturbances in neuronal energy metabolism, increased oxidative stress, and dysfunctional mitochondria. Consequently, increasing the level of NAD+ levels may have potential therapeutic value in alleviating PD symptoms. This chapter provides an overview of NAD+ functions in PD, exploring the possibility of improving mitochondrial function, reducing oxidative stress and neuroinflammation by increasing NAD+ levels.