  The scale parameter $\Lambda_{\overline{MS}}$ is computed on the lattice in
the quenched approximation and for $N_f = 2$ flavors of light dynamical quarks.
The dynamical calculation is done with non-perturbatively $O(a)$ improved
Wilson fermions. In the continuum limit we obtain
$\Lambda_{\overline{MS}}^{N_f=0} = 243(1)(10)$ MeV and
$\Lambda_{\overline{MS}}^{N_f=2} = 217(16)(11)$ MeV, respectively.
