Isotactic and optically active poly(D-lactic acid) (PDLA) and phenyl-substituted poly(lactic acid)s (Ph-PLAs), i.e., poly(D-phenyllactic acid) (Ph-PDLA) and poly(L-phenyllactic acid) (Ph-PLLA), were synthesized and stereospecific interactions between the synthesized polymers were investigated by their thermal properties and crystallization behavior using differential scanning calorimetry (DSC). The DSC measurements indicated that PDLA is miscible with Ph-PLAs and that the attractive interaction between PDLA and L-configured Ph-PLA is higher than that between PDLA and D-configured Ph-PDLA. In other words, the latter result means that poly(lactic acid) (PLA) has a higher stereoselective attractive interaction with Ph-PLA with the reverse configuration than with Ph-PLA of the same configuration. These results strongly suggest that PLA-based materials with a wide variety of physical properties and biodegradability can be fabricated by blending them with substituted PLAs with the reverse and same configurations.