AbstractThe influence of temperature on the impact behavior of unidirectional glass fiber‐epoxy composite was studied in the range of −20 and 150°C using a 3‐point drop weight test at a constant impact velocity of 2.2 m/s (5 mph). The impact energy per unit deformed volume was found to be very sensitive to the ratio length/thickness of the specimens. When the ratio was 4, the impacted specimens exhibited extensive delamination (shear failure) and the energy absorbed by the composite was about 14 MJ/m3between −20 and 100°C, and 18 MJ/m3at 150°C. At length/thickness above 16 the failure was mostly in tension, and the impact energy approached a constant value of about 3.5 MJ/m3, independent of t