Improving the sensitivity and selectivity of ammonia gas sensors at room temperature is essential for the development of self-powered sensors to expand their operational range in various environments. The strategy employed in this study to achieve this goal involves combining reduced graphene oxide (rGO), known for its excellent electrical properties, with SnO2, which has been reported to have ammonia-sensing capabilities. For this purpose, the rGO-SnO2 nanocomposite was synthesized using a two-step pyrolysis and chemical deposition method, and its ammonia gas sensing performance was evaluated. Structural characterization of the synthesized sample was conducted using XRD, BET, SEM, PL, EDX and FTIR techniques. The sensor's response to different concentrations of ammonia gas at room temperature was investigated, and the results showed a 5.2% response at 800 ppm and a low detection limit of 1.43 ppm for this gas. In addition to its high selectivity for ammonia gas, the sensor also demonstrated stability and repeatability.