Objective <p>To evaluate the effect of polishing systems on the color and roughness of conventional and bulk-fill nanofilled resins, compared to conventional and bulk-fill nano-hybrid resins with S-PRG fillers.</p> Materials and methods <p>Discs (<i>n</i> = 12) were fabricated from the following resin composites: conventional nanofilled resin (Filtek Z350 XT, 3&#xa0;M), bulk-fill nanofilled resin (Filtek One Bulk-Fill, 3&#xa0;M), conventional nano-hybrid resin with S-PRG fillers (Beautifil II LS, Shofu), and bulk-fill nano-hybrid resin with S-PRG filler (Beautifil Bulk Restorative, Shofu). Polishing was conducted using multi-grit aluminum oxide abrasive discs (Sof-Lex Pop On, 3&#xa0;M) or a single-grit aluminum oxide tip (OneGloss, Shofu). Roughness (Ra) and color (CIEL*a*b*, ΔE_ab and ΔE₀₀) were assessed at baseline, post-polishing, and post-coffee staining. Surface micromorphology was analyzed using scanning electron microscopy (SEM).</p> Results <p>Roughness increased after polishing with the aluminum oxide tip for all materials (<i>p</i> &lt; 0.0001; Mann–Whitney). Bulk-fill nanofilled resin showed increased roughness, while conventional nano-hybrid resin with S-PRG filler showed decreased roughness after multi-grit disc polishing (<i>p</i> &lt; 0.0001; Mann–Whitney). Coffee staining significantly increased the roughness in resin composites with S-PRG filler (<i>p</i> &lt; 0.0001; Mann–Whitney). All resin composites exhibited reduced L* and b* (<i>p</i> &lt; 0.05; generalized linear mixed models for repeated measures) and increased a* (<i>p</i> &lt; 0.05; Friedman and Nemenyi) values after coffee staining. ΔE_ab and ΔE₀₀ were significantly higher for bulk-fill nano-hybrid containing S-PRG filler, irrespective of polishing type (<i>p</i> &lt; 0.0001; Friedman and Nemenyi). SEM analysis revealed surface degradation and/or particle loss in resin composites with S-PRG filler (conventional and bulk-fill) post-polishing. Single-grit polishing resulted in greater surface irregularities across all resins.</p> Conclusion <p>Polishing systems significantly influence resin composite roughness based on their composition, with single-grit polishing causing the highest roughness. Bulk-fill nano-hybrid resin composite with S-PRG filler exhibited the greatest color and roughness changes post-staining.</p> Clinical relevance <p>Bulk-fill resin composite with S-PRG filler demonstrated lower color and surface stability. Importantly, these changes were significantly mitigated when polished using a multi-stage polishing system.</p>