A boron-containing UV-curable oligomer was derived from linseed oil, phenylboronic acid and glycidyl methacrylate to use in flame-retardant coating applications. The synthesized UV-curable oligomer was characterized for its structural and physicochemical properties by means of Fourier transform infrared (FTIR), 1 H and 11 B-nuclear magnetic resonance (NMR) spectroscopy techniques. The boron-containing UV-curable oligomer (BELO) was added to a conventional polyurethane acrylate (PUA) at varying concentrations ranging from 10 to 40 wt% in the presence of a photoinitiator and a reactive diluent. LOI and UL-94 tests were performed to understand the flame-retardancy behavior of the synthesized BELO oligomer, and the results revealed that the flame retardancy of UV-curable coatings enhanced as the percentage of BELO oligomer in the coating formulations increased. The glass transition temperature (T g ) and thermal stability of cured coatings were analyzed by differential scanning calorimetry and thermogravimetric analysis, respectively. The TGA analysis showed that char yield at 600 °C increased by increasing the BELO oligomer content. The mechanical properties, and stain, solvent, and chemical resistance and thermal behavior of the coatings were investigated. Incorporation of BELO into the PUA coating formulations and the comparison of the properties of BELO-incorporated PUA coatings with those of the conventional PUA coating exhibited interesting results.