In this work, a comprehensive study on the wet chemical etching of silica substrates is presented. A thin monolayer of preformed Au NPs is dip-coated on the surface and used as an etchant mask. The effect of etching time, the size of the coated NPs, and the concentration of the etching solution on the obtained surface structures are evaluated. The effect of different etching parameters is investigated for both bare and Au NP-coated silica. The optical transmittance is measured and related to the formed surface structures obtained under different experimental conditions. These studies are used to optimize the best etching conditions for the Au NP-masked silica substrate to acquire moderately good scattering and modulate the transmittance. The possible mechanisms involved in the etching of SiO 2 are also discussed in detail. The outcome of the present work helps to identify different wet chemical etching conditions for surface texturing of silica-based substrates. The low-temperature route adapted here also makes it suitable for extension to other polymeric substrates.