Food safety and quality control are critical components of public health and global trade. Conventional analytical techniques such as chromatography, culture-based microbial assays, and immunological methods, although reliable, are often time-consuming, labor-intensive, and require sophisticated laboratory infrastructure. In recent years, nanosensor technology has emerged as a transformative tool in food analysis due to its high sensitivity, rapid detection capability, portability, and potential for real-time monitoring. Nanosensors utilize nanomaterials such as gold nanoparticles, carbon nanotubes, graphene, quantum dots, and magnetic nanoparticles to detect chemical contaminants, pathogens, toxins, allergens, pesticides, and spoilage indicators at extremely low concentrations. This chapter explores the principles, classifications, mechanisms, and applications of nanosensors in food safety and quality control. Various types of nanosensors—including electrochemical, optical, piezoelectric, and nano-biosensors—are discussed with emphasis on their working principles and detection strategies. Applications in detecting foodborne pathogens (e.g., Salmonella, Listeria), pesticide residues, heavy metals, mycotoxins, and adulterants are examined. The integration of nanosensors with smart packaging systems and Internet of Things (IoT)-based monitoring platforms is also highlighted. Despite their immense potential, challenges such as regulatory concerns, toxicity risks, commercialization barriers, cost, and standardization remain significant. The chapter concludes with future perspectives emphasizing miniaturization, multiplex detection, wearable food sensors, and AI-integrated diagnostic systems. Nanosensors represent a promising frontier in ensuring safer, higher-quality food systems and supporting sustainable global food security