This work analyses the influence that the areal density of a composite thin-plate, made of glass-fibre woven laminates and subjected to high-velocity impact, exerts on perforation-threshold energy, contact time, and energy-absorption mechanisms. The perforation-threshold energy increased with the areal density. Also, the contact time increased at impact energies above the perforation-threshold energy and decreased below this threshold. The main energyabsorption mechanisms at impact energies close to that causing perforation were found to be the deformation and failure of the fibres, regardless of the areal density. For higher impact energies, the main mechanisms were fibre failure and the energy absorbed by acceleration of the laminate.