Objective: The aim of this study was to determine the effects of low-level laser therapy (LLLT) on wound healing at free gingival graft (FGG) donor sites. Materials and methods: Forty patients requiring FGG were selected for this randomized, controlled, and double-blinded prospective clinical trial. The FGG donor sites were treated with LLLT and compared with an untreated control group. The Wound-Healing Index (WHI), tissue consistency, color match, and H2O2 bubbling test for the evaluation of complete wound epithelialization were recorded on the 3rd, 7th, 14th and 21st days. The pain-burning level, number of analgesics, and bleeding were recorded for 7 days. Donor area soft tissue thickness (TT) was measured at baseline and at the first month. Results: The prevalence of Complete Wound Epithelization was higher in the LLLT group than in the control group on the 14th day (p < 0.001). The bleeding was lower in the test group than in the control group during the first 2 days (p <= 0.001). Higher WHI Scores were observed in the test group relative to the control group at all visits (p <= 0.001). Color match scores were higher in the test group than in the control group at the first 3 visits (p < 0.05). The TT changed from 4.62 +/- 0.79 to 4.71 +/- 0.82mm in the LLLT group and from 4.23 +/- 0.62 to 4.01 +/- 0.68mm in the control group. Conclusions: It can be concluded that LLLT enhances FGG donor site wound healing and preserves TT at palatinal donor sites.