Triple gauge boson couplings are measured from W-pair events recorded by the OPAL detector at LEP at centre-of-mass energies of 183 -- 209 GeV with a total integrated luminosity of 680 pb-1. Only CP-conserving couplings are considered and SU(2)xU(1) relations are used, resulting in four independent couplings, kappa_gamma, g1z, lambda_gamma and g5z. Determining each coupling in a separate fit, assuming the other couplings to take their Standard Model values, we obtain
kappa_gamma = 0.88^+0.09_-0.08
g1z = 0.987^+0.034_-0.033
lambda_gamma= -0.060^+0.034_-0.033
g5z = -0.04^+0.13_-0.12
where the errors include both statistical and systematic uncertainties. Fits are also performed allowing some of the couplings to vary simultaneously. All results are consistent with the Standard Model predictions.