A resistive random-access memory based on an Al/SnOx/Pt structure is demonstrated. The SnOx thin films were prepared by DC sputtering at room temperature and different post-deposition thermal treatments carried out. We observe a significant improvement of bipolar resistive switching characteristics after annealing at 300 °C in nitrogen. The obtained memory devices show good stability with a relatively long retention time, exceeding 105 s. The resistance ratio remains above 55 within the duration of 100 endurance cycles. An interface modified space-charge-limited-current model is proposed as a possible switching mechanism. The achieved characteristics of the resistive switching in SnOx films seem to be a promising candidate for nonvolatile memory applications.