The article provides a comprehensive review of nanoemulsions, advanced drug delivery systems designed to overcome the limitations of conventional methods. Nanoemulsions are nano-sized emulsions, typically ranging from 20 to 200 nm in droplet size, that enhance the delivery of active pharmaceutical ingredients. They are thermodynamically stable isotropic systems formed by mixing two immiscible liquids with the help of surfactants and co-surfactants. The review covers the formulation, preparation methods, characterization techniques, evaluation parameters, and applications of nanoemulsions. Key advantages include improved bioavailability, non-toxicity, enhanced physical stability, and the ability to solubilize lipophilic drugs. The main components of nanoemulsions are oil, emulsifying agents, and aqueous phases. Preparation methods include high-energy emulsification (e.g., ultrasonic emulsification, high-pressure homogenization) and low-energy emulsification (e.g., phase inversion temperature, spontaneous emulsification). Characterization techniques involve droplet size analysis, viscosity determination, dilution tests, drug content analysis, polydispersity measurement, dye tests, refractive index measurement, pH measurement, zeta potential measurement, fluorescence tests, percentage transmittance, conductance measurement, and filter paper tests. The article concludes by highlighting the widespread use of nanoemulsions in pharmaceutical systems, particularly for targeted drug delivery and prolonged action of medicaments, emphasizing their effectiveness, safety, and increased bioavailability.The article provides a comprehensive review of nanoemulsions, advanced drug delivery systems designed to overcome the limitations of conventional methods. Nanoemulsions are nano-sized emulsions, typically ranging from 20 to 200 nm in droplet size, that enhance the delivery of active pharmaceutical ingredients. They are thermodynamically stable isotropic systems formed by mixing two immiscible liquids with the help of surfactants and co-surfactants. The review covers the formulation, preparation methods, characterization techniques, evaluation parameters, and applications of nanoemulsions. Key advantages include improved bioavailability, non-toxicity, enhanced physical stability, and the ability to solubilize lipophilic drugs. The main components of nanoemulsions are oil, emulsifying agents, and aqueous phases. Preparation methods include high-energy emulsification (e.g., ultrasonic emulsification, high-pressure homogenization) and low-energy emulsification (e.g., phase inversion temperature, spontaneous emulsification). Characterization techniques involve droplet size analysis, viscosity determination, dilution tests, drug content analysis, polydispersity measurement, dye tests, refractive index measurement, pH measurement, zeta potential measurement, fluorescence tests, percentage transmittance, conductance measurement, and filter paper tests. The article concludes by highlighting the widespread use of nanoemulsions in pharmaceutical systems, particularly for targeted drug delivery and prolonged action of medicaments, emphasizing their effectiveness, safety, and increased bioavailability.