<p>Nanocomposites reinforced with carbon nanotubes (CNTs) or graphene-based materials have garnered increasing attention for improving the structural performance of engineering systems, owing to their exceptional mechanical properties. Accordingly, the mechanical behaviors and applicability of both nanocomposites have been intensively investigated, but the studies on both composites have been mostly investigated separately. In this context, this study intends to investigate which is better for wind turbine blade applications, where both lightweight and high-strength and high-durability are critical. The comparisons are made in terms of static bending and torsion, free vibration and fatigue life which are analyzed by finite element analyses. Finite element wind turbine models are generated based on the 61.5 m SNL reference design by Sandia National Laboratories, incorporated with the appropriate theories for deriving the effective material properties and evaluating the fatigue lives. The comparative numerical experiments are carried out for CNT- and graphene-reinforced wind turbine blades as well as the conventional glass fiber reinforced (GFRP) one. The numerical results reveal that the performance of conventional GFRP wind blade has been remarkably improved when GFRP was replaced with carbon-based nanocomposites. Between two nanocomposites, the graphene-reinforced composite is found to be better suited for wind turbine applications.</p>