Abstract: The influence of the direction of overhanging grooves on the suppression of tip-leakage vortex (TLV) cavitation is investigated experimentally and numerically, and the mechanisms behind it are discussed in detail. The results indicate that both the overhanging grooves (OHGs) with the overhanging at the suction and pressure sides show a significant suppression on TLV cavitation for a large range of gap sizes. Compared with the OHGs with overhanging at the suction side, a better suppression effect can be obtained by the OHGs with overhanging at the pressure side. Moreover, the OHGs with overhanging at the pressure side can provide a more satisfying suppression on the fluctuation of the cavity volume of TLV cavity. The experimental measurements indicate that the influence of the direction of overhanging grooves on the lift and drag coefficients of the hydrofoil is quite slight. The numerical results further indicate that the OHGs with overhanging at the pressure side can impede the flow from the pressure side to the suction side more effectively and disturb the development of TLV, which is helpful for the suppression of TLV cavitation.