The combination of various functional groups such as epoxy, acetoxy, methoxy, thiirane, aziridine on the acyl chain of soy fatty acid alkyl esters have been synthesized and evaluated as plasticizers in poly vinyl chloride (PVC) applications. Numerous synthetic procedures such as epoxidation, methoxylation, acetylation, thiiration, and aziridination were used for synthesizing multifunctional soy fatty acid alkyl esters. Epoxidized soybean oil fatty acid alkyl ester served as the key intermediate to incorporate most of the functional groups on the fatty acid backbone. The physical and analytical properties of bioplasticizers such as acid and saponification values are acceptable for plasticizer applications. The high viscosity and darker color of aziridine and thiirane derivatives limit their usefulness, whereas the physical properties of the other derivatives were acceptable. The plasticizer evaluation of methoxy, acetoxy soy fatty acid esters (methyl and n-butyl) demonstrated good compatibility with PVC, high efficiency (Shore Hardness) and gelling properties and were comparable to commercial plasticizer, diisononylphthalate (DINP).