Poly (lactic acid) (PLA) has gained attention due to its mechanical performance, optical transparency, renewability, biocompatibility and biodegradability in recent past. The slow crystallization kinetics, poor thermal stability, brittleness and process complexity limit its practical applications. Hence, crystallization behavior of PLA was studied enormously in past to improve its performance. Here, in particular, crystallization behavior of poly (l -lactic acid) (PLLA) and its different forms (in blends, in composites, and after adding nucleating agents, etc.) are described.