This study aims to investigate the thermal, mechanical, and flammability properties of glass fiber (GF) reinforced PLA/PC composites. PLA/PC (50:50) blend was compounded and used as the control sample. Loading levels of GF were altered as 5, 10, 15, and 30 wt%. All composites were produced in a microcompounder and subsequently molded by injection molding. The properties of the composites were investigated by limiting oxygen index (LOI), tensile test, thermogravimetric analysis, differential scanning calorimetry, scanning electron microscope, and cone calorimetry test. The maximum tensile strength value was observed for 30 wt% GF reinforced composite as 110.18 MPa. Similar initial degradation temperatures were obtained for the composites compared to the PLA. The maximum LOI value was determined as 23.1 for 30 wt% GF reinforced PLA/PC among the produced composites. Besides, it is observed that the addition of GF significantly decreased the total heat release rate.