SUMMARY Background The objective was to investigate the radiopacity of 11 commercial posterior restorative materials by establishing their mean gray values (MGVs) and comparing them with dental hard tissues. Methods and Materials Five-disc specimens were prepared for each of the following materials: Cerasmart 270 CAD/CAM block A3LT (CS), Amalgam (A), Ketac Molar A3 (KM), Cention-N A2 (CN), G-aenial Universal Flo AO2 (GO2) and A2 (G2), Ever-X Flow Dentine (EXD) and Bulk (EXB) shades, Equia Forte HT Fil A2 (EF2) and A3 (EF3), and Equia Fil A3 (E3). Freshly extracted maxillary premolar teeth were used as a control. The MGVs of specimens and a 10-step aluminum stepwedge (Al) were measured with Adobe Photoshop. ANOVA and Dunnett T3 tests were used to assess the significance of the differences (α=0.05). Results Statistically significant differences were revealed between some of the groups. Amalgam had the highest radiopacity. The radiopacity of dentin and CS were close to that of 1 mm Al. G2, KM, GO2, EXB, and EXD showed higher mean radiopacity than dentin. Enamel had a radiopacity equivalent to 2 mm Al. CN, EF2, and E3 had higher mean radiopacity than enamel. Conclusions All materials met the ISO requirements. Alkasite and reinforced glass ionomer restoratives demonstrated higher mean radiopacity than the posterior flowable composites. Material shades did not affect the radiopacity.