In this study, binary and ternary blends of polylactic acid (PLA), poly[(butylene adipate)-co terephlate] (PBAT) and poly[(butylene succinate)-co adipate] (PBSA) were prepared through injection molding (IM). Two different PLAs with low and high D-lactide contents (semi-crystalline and amorphous, respectively), as well as their mixture were used as the matrix phase in both binary and ternary blend systems. PLA phase, was fixed at 75 wt % or 50 wt % whereas the corresponding remaining 25 wt% or 50 wt% were either PBAT, PBSA, or equal mixture of PBAT and PBSA. To predict the morphology of the ternary blends, interfacial tension between each two polymers and spreading coefficient values were calculated by using Harkins equation. Negative values of spreading coefficient indicated a partial wetting morphology where droplets of one of the phases locate at the interface and demonstrate a three-phase contact. The effects of PBAT, PBSA, or their mixture, semi-crystalline, amorphous PLAs, or their mixtures, and varying blending ratios on the morphology of the blends were explored through using a scanning electron microscopy (SEM). Subsequently, the materials and morphological variation influences on the mechanical properties of blends were investigated and compared using tensile and three-point bending tests. Mechanical properties of the blends exhibited a dramatic improvement in elongation at break with increasing PBAT content (25 wt % to 50 wt %). Ternary blend containing 12.5 wt % PBAT and 12.5 wt % PBSA were shown to have superior flexural strength in comparison with binary blends.