<p>ABSTRACT&nbsp;</p><p>Objective: This&nbsp; study's objective was to evaluate the flexural strength of the five restorative materials.&nbsp;</p><p>Materials and Metods: The specimens were prepared from five materials: a high viscosity GIC (Fujı IX GP; GC, Tokyo, Japan), a resin-modified GIC (Fujı II LC; GC, Tokyo, Japan), a nano-filled resin composite (Estelite Σ Quick; Tokuyama, Tokyo, Japan) and a micro-hybrid resin composite (Charisma Smart; Heraeus Kulzer, Hanau, Germany), a giomer (Beautifil II; Shofu, Kyoto, Japan). A teflon mold was used to create the fifteen bar-shaped specimens from each material (n=15). To produce a flat surface, the specimens were gently polished by hand using 1,000- and 1,500-grit wet silicon carbide papers in a circular motion. Each specimen received a quick rinse with tap water in between each grit. All the samples were made at room temperature (21± 1 °C), with a relative humidity of 55 percent. Each group spent 24 hours before testing in distilled water at 37°C. The flexural strength was evaluated according to ISO standards on a universal testing machine. The Kolmogorov-Smirnov test was used to determine if the data were normally distributed. One-way ANOVA and Tukey HSD posthoc tests were used to compare the mean flexural strength values across the groups (P = 0.05).&nbsp;</p><p>Results: The high viscosity GIC had the lowest flexural strength value (p&lt;0.05). The giomer, nano-filled resin composite, and micro-hybrid resin composite had the highest flexural strength values (p&lt;0.05). There were no statistically significant differences between the flexural strength values of the giomer, nano-filled resin composite, and micro-hybrid resin composite (p&gt;0.05). Statistically, the flexural strength of the resin-modified glass ionomer was higher than that of the high viscosity glass ionomer (p&lt;0.05). However, compared to giomer, the nano-filled resin composite, and the micro- hybrid resin composite, the flexural strength value of the resin-modified glass ionomer was statistically lower (p&lt;0.05).&nbsp;</p><p>Conclusion: While the addition of resin to glass ionomer cement improves the flexural strength of the material, there is no difference between the flexural strength values of resin composites and giomer.</p><p>KEYWORDS: High viscosity glass ionomer cement, Resin-modified glass ionomer cement, Giomer, Flexural strength.</p>