Aim <p>The aim of this study was to compare the efficacy of photobiomodulation therapy (PBMT) and injectable platelet-rich fibrin (i-PRF) applied to the palatal donor site following harvesting a free gingival graft (FGG), regarding wound healing and postoperative patient morbidity.</p> Materials and methods <p>A total of 36 patients who required FGG were randomly assigned into 3 groups; PBMT (<i>n</i> = 12), i-PRF (<i>n</i> = 12), and control (<i>n</i> = 12). Wound healing was evaluated at the clinic follow-up examinations of the patients at 3, 7, 14, 21, and 30 days postoperatively. Evaluations were made with the palatal early healing index, the hydrogen peroxide foaming test, and measurements of the wound size with Image J program on photographs. Pain severity was measured with a VAS, and analgesia consumption was recorded. Data were analyzed with ANOVA, Kruskal–Wallis, Chi-square, and Friedman tests.</p> Results <p>The total wound surface area on days 3,7,14, and 21 was determined to be significantly greater in the control group than in the test groups. The VAS pain scores on days 3 and 14 were found to be significantly higher in the control group than in the test groups. Analgesia consumption in the control group was higher than in the PBMT group on postoperative day 3. On days 5 and 7, the control group required significantly more analgesia than the i-PRF group.</p> Conclusion <p>The application of i-PRF and PBMT was seen to accelerate wound healing, and decrease pain levels and the need for analgesia of the patients.</p> <p>Registry: ClinicalTrials.gov, NCT06744270, Registration date: 19 December 2024.</p> Clinical relevance <p>The shorter time, lower costs and need for less clinical follow-up of&#xa0;i-PRF rendered it more advantageous than PBMT.</p>