In this work, vibration behaviour of aluminium alloy 5083-reinforced nanoclay–montmorillonite nanocomposites was studied to have a better dynamic property for lightweight structural applications without affecting the mechanical property. Composite samples with various weight percentages of nanoclay were fabricated using stir casting method and achieved uniform dispersion with strong interfacial bonding between matrix and reinforcement. The influence of nanoclay in the aluminium alloy composite was also studied by different material characterization techniques such as scanning electron microscope, energy-dispersive X-ray spectroscopy, X-ray diffraction and microhardness test. From the study, it was concluded that the microhardness value of the aluminium alloy-reinforced nanoclay was decreased with the increase in nanoclay weight percentage. The mechanisms related to the shifting of frequencies were studied to know the effectiveness of reinforcement. The natural frequencies of the aluminium alloy 5083-reinforced nanoclay composites were found to be increased with the addition of 2 wt% of nanoclay in comparison with AA 5083 and 1 wt% of nanoclay. © 2019, The Indian Institute of Metals - IIM.