Waterborne epoxy coatings provide an environmentally friendly alternative to traditional solvent-based systems, but often require property enhancements for many applications. This chapter explores the use of vegetable oils as renewable modifiers to improve the flexibility, adhesion, corrosion resistance, and biodegradability of these sustainable coatings. The motivation for incorporating vegetable oils stems from their availability, low cost, and inherent structures containing reactive sites along with flexible aliphatic segments. Various chemical modification routes including acrylation, maleination, epoxidation, and esterification are detailed for facilitating integration of the oils into the epoxy network during curing. Physical blending approaches like emulsion and nanoemulsion techniques are also discussed. The effects of vegetable oil modification on mechanical performance parameters such as tensile strength, flexural properties, impact resistance, and hardness are critically analyzed. Influences on thermal characteristics including glass transition temperature and thermo-oxidative stability are examined. Enhanced barrier properties against moisture and corrosive media enabled by the oils are evaluated as well. Key application areas taking advantage of the improved properties are highlighted, including protective coatings for metals, marine antifouling/anticorrosive coatings, automotive primers and topcoats, and emerging opportunities in areas like wind turbine blades. However, challenges in aspects like emulsion stability, substrate adhesion, and potential compromises at high oil loadings are identified. Finally, future research directions focused on developing multifunctional vegetable oil modifiers, hybrid filler systems, predictive structure–property models, and imparting advanced functionalities like self-healing are discussed. Overall, this comprehensive chapter establishes vegetable oil modification as a powerful, sustainable strategy for tailoring waterborne epoxy coatings to meet demanding performance requirements across industries.