Background. Interfacial failures at the cement‒ restoration interface highlights the importance of effective Surface treatment with no adverse effect on the zirconia’ s mechanical properties. This study aimed to determine the effect of different Surface treatments on dental graded zirconia’ s Surface roughness and certain mechanical properties. Methods. Forty sintered zirconia specimens were randomly divided into four groups (n = 10): control (no Surface treatment), sandblasting (SA), grinding with diamond bur (GB), and Er, Cr: YSGG laser (LS). Following Surface treatment, the Surface roughness and Surface topography of the specimens were examined. X-ray diffraction (XRD) was conducted. In addition, the biaxial flexural strengths of specimens were evaluated. The data were analyzed using one-way analysis of variance (ANOVA) and post hoc Tukey tests; the Pearson correlation coefficient was calculated between either volumetric percentage of monoclinic phase or roughness and flexural strength of specimens (α = 0. 05). Results. The GB group exhibited significantly greater Surface roughness compared to the other groups (P < 0. 005). The LS and control groups exhibited a significantly lower volumetric percentage of the monoclinic phase (P < 0. 001) than the GB and SA treatments. The SA group exhibited significantly higher flexural strength than the control (P = 0. 02) and GB groups (P < 0. 01). Furthermore, the Weibull analysis for the LS showed higher reliability for the flexural strength than other treatments. Conclusion. Er, Cr: YSGG laser treatment, with the lowest extent of phase transformation and reliable flexural strength, can be a promising choice for Surface treatment of zirconia.