Metal-Assisted Chemical Etching (MACE) has emerged as effective method to fabricate high aspect ratio nanostructures. This method requires a catalytic mask that is generally composed by a metal. Here, we challenge the general view that the catalyst needs to be metal by introducing Oxide-assisted Chemical Etching (OACE). We perform etching with metal oxides such as RuO 2 and IrO 2 , by transposing materials used in electrocatalysis to nanofabrication. These oxides can be solution-processed as polymers exhibiting similar capabilities of metals for MACE. Nanopatterned oxides can be obtained by direct nanoimprint lithography or blockcopolymer lithography from chemical solution on large scale. High aspect ratio silicon nanostructures were obtained at the sub-20 nm scale exclusively by cost-effective solution processing by halving the number of fabrication steps compared to MACE. More in general, OACE is expected to stimulate new fundamental research on chemical etching assisted by other materials providing new possibilities for device fabrication.