To meet the demands of new applications, it is required to improve the performance of high density polyethylene (HDPE) in terms of properties such as stiffness and rigidity by forming composites. Pashupati Pokharel, Hyunmin Bae, Jung-gyu Lim, Kyoung Yong Lee, and Sunwoong Choi investigate the effect of graphene nanoplatelets (GNPs) and titanate coupling agent on morphology and mechanical properties of HDPE nanocomposites. The cover shows a SEM image of the tensile failure surface of a GNP/HDPE composite with titanate, in which a typical ductile fracture with a considerable large plastic deformation into numerous fibrils was observed. (DOI: 10.1002/app.42073)