Polylactide (PLA) was successfully plasticized by blending with diethylene glycol monobutyl ether adipate (DGBEA). The results showed that PLA and DGBEA had close solubility parameters, so PLA was miscible with DGBEA. The dynamic storage modulus and complex viscosity in the melt state of the blends decreased compared with neat PLA. DGBEA lowered the glass transition temperature and the cold crystallization temperature of PLA which were good indications of the extent of the plasticizing effect provided by DGBEA. However, the crystallinity and spherulite size of PLA gradually increased with increasing DGBEA content. In all PLA/plasticizer blends investigated, a stepwise change in the mechanical properties of the system was observed. The elongation at break and impact strength drastically increased, whereas tensile strength and modulus decreased. The DGBEA plasticizer had low tendency to migrate. Thus, the DGBEA was a promising plasticizer alternative for bioplastics as they also retained the biodegradable nature of these biobased materials.