The development of uniform electrolyte thin films minimizes the ohmic loss of ceramic oxide electrolyzers and/or fuel cells, increasing their efficiency. In this work, thin films of BaZr0.85Y0.15O3-d (BZY) electrolyte have been obtained over a 40 vol% Nickel–BaZr0.85Y0.15O3-d (Ni–BZY) cermet anode support by spin coating. To facilitate this aim, stable suspensions have been tailored, by methodically determining suitable solvents and additives (surfactants and/or thickeners). Sedimentation studies showed that ethanol and 1-methoxy-2-propanol can produce similar, stable 5% w/w BZY suspensions. The best result was obtained by simultaneously adding 1.5 wt% of ZEPHRYM PD 7000 (a commercial polyoxyalkylene amine derivative surfactant) and 0.3 wt% of polyvinyl butyral (PVB) in 1-methoxy-2-propanol. Suspensions of 1-methoxy-2-propanol with higher powder concentration (25% w/w) also show good stability that was improved by the addition of 1 wt% of ZEPHRYM. Using this system, dense BZY films of around 14 µm thick could be successfully obtained at 1500 °C.