Numerical estimates are reported for the exchange-stiffness constant ${\rho }_s$ of a dilute, Ruderman-Kittel-Kasuya-Yosida—coupled spin-glass at zero temperature. Conventional stiffness behavior is found, with no resolved trend in ${\rho }_s$ over simulation volumes of constant cross section and lengths in the ratio 1:2:3. The value of ${\rho }_s$ is found to scale as $c^{\frac{4}{3}}$ ($c$ being the atomic fraction of magnetic ions), as expected for an $r^{-3\mathrm{}}$ interaction potential and to be ∼25 times smaller than the value for a comparable ferromagnet. When one uses the Halperin-Saslow expression for the spin-wave dispersion constant, a parabolic density of spin-wave modes is found which is consistent with the low-frequency ($\hslash \omega \lesssim 0.2$ meV) density of excitations recently given for 0.9 at.% Mn in Cu from numerical simulation studies.