Polylactic acid (PLA) is a biobased product and a compostable aliphatic polyester that has been studied for use in several applications over the last decade. Many properties of PLA, such as strength, stiffness, and gas permeability, have been found to be comparable to those of traditional petrochemical-based polymers. However, PLA-based materials exhibit a number of limitations for specific applications, such as slow biodegradation rate, high cost, and low toughness. The modification of PLA using the polymer blending technique to achieve suitable properties for different applications has been receiving significant attention over the past few years. Hence, the aim of this work is to summarize the current developments regarding the preparation and properties of PLA polymer blends. In this review, the recent advances in PLA preparation are broadly introduced. In addition, the miscibility and compatibilization strategies of PLA polymer blends are discussed. The preparations and characterizations of PLA blends with both biodegradable and non-biodegradable polymers are outlined. Finally, the biodegradation, mechanical properties, and potentiality of PLA blends are presented.