A method for producing a reflection-reducing layer system on a substrate and a reflection-reducing layer system are disclosed. According to an embodiment the method includes depositing a refractive index gradient layer on the substrate by co-evaporation of an inorganic material and an organic material, wherein the refractive index gradient layer has a refractive index which decreases in a growth direction, depositing an organic layer above the refractive index gradient layer, and producing a nanostructure in the organic layer by a plasma etching process.