Parkinson's disease (PD) is the second most common neurodegenerative disease after Alzheimer's disease (AD). Genetic predisposition and immune dysfunction are involved in the pathogenesis of PD. Notably, peripheral inflammatory disorders and neuroinflammation are associated with PD neuropathology. Type 2 diabetes mellitus (T2DM) is associated with inflammatory disorders due to hyperglycaemia-induced oxidative stress and the release of pro-inflammatory cytokines. Particularly, insulin resistance (IR) in T2DM promotes the degeneration of dopaminergic neurons in the substantia nigra (SN). Thus, T2DM-induced inflammatory disorders predispose to the development and progression of PD, and their targeting may reduce PD risk in T2DM.