The quest for more precise, safer, and effective drug delivery has accelerated the exploration of stimuli-responsive systems, among which light-activated platforms offer a unique advantage due to their controllability and non-invasiveness. Chitosan, a natural polysaccharide known for its biocompatibility, biodegradability, and chemical modifiability, has emerged as a promising material in the design of advanced drug delivery vehicles. This chapter discusses the critical properties of chitosan that support its application in light-responsive systems, highlighting its structural versatility, mucoadhesive characteristics, and capability to encapsulate a broad range of therapeutic agents. It further explores the mechanisms by which light triggers drug release, emphasizing photochemical and photothermal processes, and examines the synthesis and characterization techniques crucial for the development of chitosan-based nanocarriers. Applications of these systems are reviewed across therapeutic areas such as oncology, antimicrobial treatments, and neurological disorders. This chapter also addresses the challenges facing clinical translation, including stability, targeting specificity, and scalability, and outlines recent innovations in chemical modification of chitosan to enhance its performance. Together, these advances position chitosan-based light-activated systems as a compelling strategy for future precision medicine applications.