Abstract: In this work, resonant and elastic properties of single crystal gold nanowires have been studied through classical molecular dynamics simulations. The considered nanowires have perfect square cross sections and are oriented with the [100] direction along the wire axis and with 100 side surfaces. Three different sizes were simulated; 4.08×4.08 nm2, 5.71×5.71 nm2, and 7.34×7.34 nm2 cross sectional dimensions, with the respective unrelaxed lengths 49.0 nm, 68.5 nm, and 88.1 nm and the simulations were performed at two different temperatures, 4.2 K and 300 K. Tensile simulations reveal, that the stiffness decreases with decreasing size, and that the size dependence for nanowires at 4.2 K can be accurately described using the concept of surface energy. Comparing results from the resonant simulations reveals that the fundamental eigenfrequency is in good agreement with predictions from Bernoulli–Euler continuum beam theory when the size dependence of the stiffness is taken into account. The eigenfrequencies of the first and second excited modes turn out to be low in comparison with analytical Bernoulli–Euler continuum calculations.