Adhesively bonded joints play a vital role in improving the structural performance of 3D-printed components. This research aims to examine the effect of graphene inclusion on the failure load and vibrational behavior of polylactic acid flat-joggle-flat (FJF) joints prepared using fused deposition modeling. The present research focused on the effect of print directions (0°, 45°, 90°) and the inclusion of graphene nanofiller (0.25, 0.50, 0.75, and 1.00 wt%) on the performance of FJF joints. The effect of raster direction on mechanical properties was examined by tensile testing of dog-bone samples. Results showed that 0° print orientation had higher tensile strength compared to other printing directions. Shear testing of FJF joints indicated that the inclusion of graphene has enhanced the strength of 3D-printed FJF joints by 61.18%. Fractography results showed that the formation of the shear band with the inclusion of 0.50 wt% graphene helps to distribute the stress more evenly and prevent catastrophic failure of the FJF joint. The free vibrational test revealed that the inclusion of 0.50 wt% graphene had improved the natural frequencies, as the presence of graphene-enhanced the interfacial bonding between FJF adherend and adhesive. Highlights: 0° print orientation had higher tensile strength than other printing directions. Inclusion of graphene-enhanced the shear strength of flat-joggle-flat (FJF) joints by 61.18%. Shear band formation delayed the failure of graphene-reinforced FJF joints. FJF reinforced with 0.50 wt% graphene had adherend failure. FJF joint added with 1.0 wt% graphene had lower natural frequencies. © 2024 Elsevier B.V., All rights reserved.