The present disclosure relates to a cover window for a flexible display device including a polymer substrate including a polyamide resin; and a hard coating layer formed on at least one surface of the polymer substrate, wherein a yellow index of the polymer substrate measured in accordance with STM E 313 is 4.00 or less, and an elastic modulus of the polymer substrate measured at a strain rate of 12.5 mm/min in accordance with ISO 527-3 is 4 to 9 GPa.