A new type of plasticizer, epoxidized cardanol butyl ether (ECBE), was synthesized via etherification and epoxidation. Successful synthesis was confirmed from Fourier transform infrared, 1 H NMR and 13 C NMR spectra. The obtained product was evaluated by adding it to poly(vinyl chloride) (PVC) incorporated with dioctyl phthalate (DOP). Mechanical and thermal properties of PVC blends were studied using tensile testing, thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). Processability, migration and volatility of plasticizing systems were also investigated. Tensile tests found a maximum increase of 17.8% in elongation at break. DMA results indicated that glass transition temperature shifted to lower temperature with a maximum decrease of 5.76 ∘ C. TGA results revealed that PVC blends with higher content of ECBE had higher thermal stability; initial degradation temperature, 50% weight loss temperature and the first peak degradation temperature increased by 15.3, 14.8 and 4.1 ∘ C, respectively. Processing time was extended from 11.56 to 59.94 min. The plasticizing performance of migration and volatility resistance were higher than those of neat DOP.