UV-curable coating has gained popularity in many industries as an efficient yet environmentally friendly coating. This article presents a comprehensive study on the effect of different reactive diluents on the film properties of UV-curable coating. Palm-oil-based alkyd was chosen as the resin in this work due to its compatibility with many different types of reactive diluents. A total of four different types of commercially available reactive diluents were used in this study, and the effects on the physicochemical and thermal properties of the coatings were investigated. The Flynn–Wall–Ozawa approach was employed to investigate the thermal stability of the coatings with respect to the activation energy of decomposition, Ed. The results show that some of the coatings formulated with different types of reactive diluents exhibit different properties, such as different tack-free time, pencil hardness, film adhesion, and thermal stability. The factors contributing to the observed differences include the functionality and reactivity of –C=C– in the reactive diluents.