The objective of this study was to evaluate the 24-month clinical performance of three different bulk-fill restorative resin materials in class II restorations. Forty patients with at least three approximal lesions in premolar and molar teeth participated in the study. A total of 120 class II cavities were restored using Tetric EvoCeram Bulk Fill (n=40), SureFil SDR flow + Ceram.X mono (n=40), and everX Posterior + G-aenial Posterior (n=40) with their respective adhesives according to the manufacturers' instructions. All restorations were placed by one operator. The restorations were evaluated at baseline and at six, 12, 18, and 24 months using modified US Public Health Service criteria by one examiner. The restoration groups for each category were compared using the Pearson chi-square test, while the Cochran Q-test was used to compare the changes across different time points within each restorative material (p<0.05). At the end of 24 months, 94 restorations were evaluated in 33 patients, with a recall rate of 82.5%. There were no statistically significant differences between the groups in terms of retention (p>0.05). At the 24-month recall, two restorations from the SureFil SDR flow + Ceram.X mono group and four from the everX Posterior + G-aenial Posterior group showed slight marginal discoloration and were rated as bravo. No marginal discoloration was observed in any of the Tetric EvoCeram Bulk Fill restorations. Six restorations from the Tetric EvoCeram Bulk Fill group, six from the SureFil SDR flow + Ceram.X mono group, and 12 from the everX Posterior + G-aenial Posterior group received bravo scores in terms of marginal adaptation. No difference was found among the three groups for any of the evaluation criteria tested (p >0.05). There were statistically significant differences between the baseline and 24-month recall in the everX Posterior + G-aenial Posterior group in terms of marginal discoloration (p<0.05). For marginal adaptation, a significant difference was observed between baseline and 24 months for all the restorative resins (p<0.05). All the restorative resins tested performed similarly and showed acceptable clinical performance during the 24-month evaluation.