Background <p>This study aimed to evaluate the effect of hemp fiber (HeF) and lignin-pectin-free HeF addition on the surface roughness of poly(methyl methacrylate) (PMMA) together with the Finishing and Polishing process.</p> Methods <p>HeF and lignin-pectin-free HeF were used at a rate of 1%. This study uses three groups: Finishing groups (FG), Universal Polishing Paste groups (UP), and Lesk Polishing Liquid groups (LP). Each group has subgroups consisting of PMMA, PMMA + 1% HeF, and PMMA + 1% lignin-pectin-free HeF. ‘finishing’ and ‘polishing’ processes were applied to the prepared samples. Surface roughness was measured ‘finishing’ and ‘polishing’ processes using a profilometer. SEM and EDX analyses were performed in the characterization. One-way ANOVA evaluated surface roughness. <i>P</i> = 0.05 was set as the level of statistical significance.</p> Results <p>Statistical analysis showed that there were significant differences in surface roughness between the sample materials for PMMA + 1% HeF + ‘finishing’ (FG2) group in the ‘finishing’ process and PMMA + 1% HeF + Universal Polishing Paste (PG2) group in the ‘polishing’ process (<i>p</i> &lt; 0.05). The mean R_a values ​​of the PG group in the ‘polishing’ process were found to be significantly higher than those of the PMMA + Lesk Polishing Liquid (LP) group (<i>p</i> &lt; 0.05). The null hypothesis was rejected, and HeF increased surface roughness. ‘finishing’, with varying results, Polishing depending on the paste (PG) or liquid material (LP) used. Reducing surface roughness in dental materials is crucial to minimize microbial adhesion and colonization.</p> Conclusion <p>The findings suggest that hemp fibers increase roughness before polishing, and effective polishing can alleviate this, potentially reducing microbial adhesion and improving overall oral hygiene in clinical settings.</p>