The clarifying effect of using bis-oxalamide compounds on linear low density polyethylene (LLDPE) has been investigated for the first time. It was demonstrated that the haze of a commercial LLDPE resin, DOWLEX 2045G, can be reduced up to 50% by adding 0.2 wt % of a bis-oxalamide clarifying agent. The investigations on the crystalline morphology revealed that the density of spherulite cores increased with increasing concentration of bis-oxalamide N5. Through an investigation of structure-property relationships based on the tunable bis-oxalamide structure, it was demonstrated that the combination of linear alkyl core and cyclohexyl pendant groups showed the best clarification. The interactions of clarifying molecules were simulated using dynamic molecular simulation. The simulation suggested that the rigidity of the core functionality played a role on the hydrogen bonding in the intermolecular network, which may contribute to the macroscopic clarification performance. POLYM. ENG. SCI., 58:142-149, 2018. (c) 2017 Society of Plastics Engineers