Abstract: Pure nanocrystalline cubic yttria-stabilized zirconia (YSZ) samples have been produced at temperatures as low as 800 °C by annealing in air hybrid free-standing sol-gel-derived ﬁlms. The addition of polyvinylpyrrolidone (PVP) to the sol allows the preparation of crack free gel ﬁlms. By casting the sol onto a mercury surface, ﬁlms with thickneses in the range 80–100 μm were obtained. The thermal evolution of hybrid PVP–YSZ xerogels has been followed using FTIR spectroscopy, thermogravimetric analysis, X-ray diﬀraction and scanning electron microscopy. The inﬂuence of the polymer addition on ﬁnal ceramic structure and microstructure has been studied by changing the polymer content. The ‘‘matrix eﬀect’’ of PVP in controlling crystallite sizes has been found and related to the thermal degradation of the polymer.