  The measurement of the strong coupling alpha_S using hadronic event shape
distributions measured with the OPAL detector at center-of-mass energies
between 91 and 209 GeV is summarized. For this measurement hadronic event shape
distributions are compared to theoretical predictions based on
next-to-next-to-leading-calculations (NNLO) and NNLO combined with resummed
next-to-leading-logarithm calculations (NLLA). The combined result using NNLO
calculations is
alpha_S(MZ)=0.1201+-0.0008(stat.)+-0.0013(exp.)+-0.0010(had.)+-0.0024(theo.)
and the result using NLLO and NLLA calculations is
alpha_S(MZ)=0.1189+-0.0008(stat.)+-0.0016(exp.)=-0.0010(had.)+-0.0036(theo.),
with both measurements being in agreement with the world average.
