Experimental and computational study of flapping-wing insect at low Reynolds number is conducted in this work. The paper is broadly divided into two sections: experiments and computational fluid dynamics–based numerical analysis. A dynamically scaled wing is simulated using Overset Transonic Rotor Unsteady Navier–Stokes (OVERTURNS) computational platform, a three-dimensional Navier–Stokes solver. The computational results are compared with experimental results of an isolated flapping wing performed in an oil tank. Good agreement was observed between the experiments and numerical simulations in terms of magnitude and trend of the unsteady instantaneous lift and drag forces over the flapping cycle. A parametric study was performed to observe the influence of the kinematic, flapping frequency and pitch angle, on the force production and power requirements. As a consequence of the study, lift-to-power ratio versus average lift was identified as a principal efficiency metric to assess the performance of flapping-wing vehicles for given geometry and kinematic parameters. A clear advantage for a wing pitch angle of 40° was observed compared with that of 30° or 60°. Copyright © 2019 by the American Institute of Aeronautics and Astronautics Inc. All rights reserved.