We fabricated InSnZnO (ITZO) thin-film transistors (TFTs) with a high-permittivity (κ) ZrO2 gate insulator using a solution process and explored the microstructure and electrical properties. ZrO2 and ITZO (In:Sn:Zn=2:1:1) precursor solutions were deposited using consecutive spin-coating and drying steps on highly doped p-type Si substrate, followed by annealing at 700 °C in ambient air. The ITZO/ZrO2 TFT device showed n-channel depletion mode characteristics, and it possessed a high saturation mobility of ∼9.8 cm2/V·s, a small subthreshold voltage swing of ∼2.3 V/decade, and a negative V TH of ∼−1.5 V, but a relatively low on/off current ratio of ∼10−3. These results were thought to be due to the use of the high-κ crystallized ZrO2 dielectric (κ ∼ 21.8) as the gate insulator, which could permit low-voltage operation of the solution-processed ITZO TFT devices for applications to high-throughput, low-cost, flexible and transparent electronics.