The p21-activated kinase (PAK) family is a downstream effector of the small GTPases Cdc42 and Rac, divided into two groups: Group I (PAK1-3) and Group II (PAK4-6). PAK proteins consist of an autoinhibitory domain and a kinase activity domain. They predominantly localize to the cell cytoskeleton, cell membrane, and cell nucleus, participating in the regulation of cytoskeletal reorganization, cell migration, cell cycle control, and signal transduction. Members of the PAK family are expressed in various cell types, and their activity and expression are rigorously controlled by cellular signals and the cellular environment. Gene mutations or dysregulation are associated with various diseases, including cancer, cardiovascular diseases, and neurodegenerative disorders.