In this thesis, the structural, electrical and mechanical properties of AgxAu85-xSi15 thin film metallic glasses (TFMGs) on polymer substrates were investigated. The films were fabricated by magnetron sputter deposition from three elemental targets, which allowed to systematically vary the composition and film thickness. In contrast to crystalline metals, where the electrical resistivity increases with decreasing film thickness, AgAuSi TFMGs were found to have a decreasing electrical resistance with decreasing film thickness. Additionally, ultrathin TFMGs with a thickness of 12 nm exhibited superior mechanical properties that were linked to the suppression of shear bands, where no material damage occurred after straining the films up to 10%. In cyclic bending tests, AgAuSi TFMGs outperformed crystalline metals due to their high elastic straining limit. The combination of these remarkable properties makes AgAuSi TFMGs possible candidates for future materials in flexible electronics.