Platelet-rich plasma (PRP) has emerged as a promising biologically active adjunct in regenerative endodontics due to its high concentration of autologous growth factors that promote angiogenesis, cell proliferation, and tissue healing. Used as a scaffold and bioactive reservoir, PRP supports pulp–dentin complex regeneration, particularly in immature necrotic teeth. This review highlights the biological basis, preparation methods, and diverse clinical applications of PRP in endodontics. Despite its advantages, limitations related to standardization and growth factor release persist, emphasizing the need for further long-term clinical studies to establish predictable protocols.