In this article, we report the forming-free resistive switching behavior of a Ru/Dy₂O₃/TaN memory device incorporating a Dy₂O₃ thin film fabricated entirely through processing at room temperature. We used X-ray diffraction, secondary ion mass spectrometry, and X-ray photoelectron spectroscopy to investigate the structural and chemical features of the Dy₂O₃ film. The dominant conduction mechanisms in the low- and high-resistance states were ohmic behavior and Poole-Frenkel emission, respectively. The Ru/Dy₂O₃/TaN memory device exhibited a high resistance ratio and provided nondestructive readout and reliable data retention. This memory device has a great potential for application in nonvolatile resistive switching memory.