Gold films that are initially isotropic in the plane of the substrate following deposition at normal incidence are shown to become anisotropic as they are sputter etched with a beam of Ar+ions.Insitumonitoring of the optical transmittance at normal incidence for two polarizations during deposition and during etching shows that the effect increases with angle of incidence of the ion beam and depends strongly on the initial post‐deposition morphology of the gold film. Films with an initial globular morphology subsequently exhibit the largest anisotropy, about 1%–2% in transmittance. Fully coalesced films show no anisotropy until they break up at very small thickness. Anisotropy versus mean transmittance deposition and etch paths are quite dissimilar and are indicative of different deposition/etch island morphologies.