Neurological disorders and glioblastoma represent a significant global health burden, affecting billions of individuals and contributing to high rates of morbidity and mortality. A primary obstacle in treating these conditions is the presence of the blood-brain barrier (BBB), a protective barrier that restricts the entry of most therapeutic agents into the brain. Despite this challenge, advancements in nanotechnology, specifically the development of polymeric nanoparticles, offer promising solutions for overcoming the BBB. Key strategies include surface modifications like PEGylation to enhance circulation time, receptor-mediated targeting for specific brain cells, and stimuli-responsive nanoparticles that release drugs in response to pH or reactive oxygen species. Ultrasound-guided delivery, intranasal administration, and magnetic nanoparticle guidance further enhance targeted delivery, while multifunctional nanoparticles enable combination therapies. These nanoparticles, with their customizable properties, allow for targeted and sustained delivery of drugs to the central nervous system, providing new hope in the treatment of both neurodegenerative diseases and brain cancers. In this review, we explore recent strategies that exploit polymeric nanoparticles to improve drug delivery across the BBB, highlighting their potential in revolutionizing therapeutic approaches for neurological disorders.