Embodiments of the present invention are directed to forming a Resistive Random Access Memory (RRAM) device with a spacer for electrode isolation. In a non-limiting embodiment of the invention, a memory stack including a top electrode, a bottom electrode, and a dielectric layer between the top electrode and the bottom electrode is formed. A portion of the memory stack is removed to expose a sidewall of the top electrode and a spacer is formed on the sidewall of the top electrode. The spacer is positioned to encapsulate the top electrode, physically preventing a short between the top electrode and the bottom electrode.