Encapsulating essential oil (EO) using nanoemulsion technology enhances their stability, bioavailability, and controlled release. Nanoemulsions are colloidal dispersions of nanoscale oil droplets in water, stabilized by surfactants. They improve the solubility of hydrophobic EO, protect against degradation from heat, light, and oxygen, and ensure sustained release of bioactive properties. Methods for preparing essential oil-loaded nanoemulsions include high-pressure homogenization, ultrasonication, and solvent evaporation, enabling precise control over droplet size and distribution for optimal outcomes. This protocol book covers the materials, methods, and detailed notes for preparing essential oil-loaded nanoemulsions. It provides a step-by-step approach to encapsulating essential oils (EO) to enhance their stability, bioavailability, and controlled release. The Materials section includes essential oils, surfactants, solvents, and required equipment such as ultrasonic homogenizers and high-pressure homogenizers. The Methods section outlines the procedure for combining EO with surfactants, preparing coarse emulsions, and reducing particle size using sonication or homogenization. The detailed Notes section offers troubleshooting tips to address common challenges, such as instability, particle size issues, and long-term stability. It also highlights safety precautions, handling instructions, and best practices for optimizing nanoemulsion formulations. This book is a valuable guide for researchers and professionals working with EO nanoemulsions, providing effective strategies for encapsulation and application in various fields.