Sol–gel thin films of amorphous LaNbO x (LNO) were prepared to study the bipolar resistive switching (BRS) properties of Metal/LNO/ITO devices. We investigated the influences of film thickness, top electrode, annealing temperature, post-metal annealing (PMA), and bilayer structure on the resistive switching (RS) characteristics. In comparison to the as-deposited LNO thin film devices, the PMA-treated devices demonstrated better RS characteristics, with lower set/reset voltages (V Set /V Reset  = − 2.26V/0.9V), longer switching cycles (2466 cycles), and a > 10 1 R on /R off ratio. Furthermore, at 85 °C, the retention time exceeded 10 4 s, similar to the retention time at room temperature, indicating that random access memory (RRAM) may effectively function over 10 years. The improvement in RS characteristics can be attributed to the formation of an AlO x layer between the upper electrode and the insulating layer after PMA treatment, which increases the oxygen vacancy content and facilitates Al ion diffusion. The addition of a bilayer of Al was implemented to increase the thickness of AlO x , thereby improving the R on /R off ratio. However, this addition also degrades the RS properties of the device. Furthermore, the space charge-limited current (SCLC) conduction mechanism dominates in the high resistance state (HRS), while ohmic conduction prevails in the low resistance state (LRS) of the devices.