The fabrication of highly thermally and electrically conductive polymer materials is of interest for multiple applications, for example, in electronics packaging and biosensors. Polylactic acid (PLA), a commercially available and biodegradable polyesters, is widely used and studied since it is considered a environmentally friendly alternative to petrochemical-based synthetic polymers. In the present study, graphene nanoplatelets (GNP) reinforced PLA composites were prepared via solution blending followed by a compression molding process. Various physical and thermo-mechanical analyses were performed with the prepared composites. For instance, the electrical conductivity of PLA/GNP composites at various filler loadings was determined using four-point probe resistivity measurements. An electrical conductivity of 0.1 S/cm was achieved at a GNP loading of 12 wt%. Using the hot-disk transient plane source method, anisotropic thermal conductivity properties were evaluated. An in-plane and through-plane thermal conductivity of 0.87 W/mK and 0.58 W/mK was achieved with the addition of 6 wt% GNP, which is a nearly twofold and over fourfold increase compared to neat PLA, respectively.