Aim and objective: This study aims to evaluate the use of hyaluronic acid (HA) on the free gingival graft (FGG) applied to mandibular canines with Miller class I or II gingival recession (GR) or without attached gingiva by evaluating tissue healing, swelling, and dimensional changes. Materials and methods: This split-mouth clinical study has an examiner–patient blinded design. Eighteen patients with bilateral class I or II of Miller classification of GR in the mandibular canine region with <2 mm of attached gingiva were treated with FGG and randomly assigned to experience either natural healing (control group) or HA-assisted healing (test group). Tissue healing index, swelling, and dimensional changes were registered at baseline, 1, and 3 months post-surgery. Statistical analysis was performed to examine differences between study groups. Results: The test group showed better healing and swelling compared to the control group and these differences were statistically significant. No statistically significant difference was found for dimensional changes between groups. Conclusion: It may be concluded that within the limits of this study that the adjunctive use of HA may be beneficial in the healing process of FGG. Clinical significance: The application of HA helped improving the healing of FGG, which makes the process faster and more predictable.