Introduction. Laser therapy (LT), which stimulates natural biological processes in the application region, is frequently used in dental treatments. Objective. The aim of this study is to evaluate the effects of LT that could increase wound healing on fibroblast cells in vitro. Methods. Twenty-four hours after preparing the fibroblast cell culture plates, laser irradiation was performed 1, 2, and 3 times according to the test groups using an Nd:YAG (neodymium-doped yttrium aluminum garnet) laser with a power output of 0.5 W, 1 W, 2 W, and 3 W. Cell proliferation analysis was performed by MTT (methylthiazole diphenyl tetrazolium) assay at the twenty-fourth hour following the last laser application. Results. In terms of the laser irradiation power level, the most proliferation was observed in 1 W and 2 W application groups. Although a statistically significant increase was observed, particularly at 0.5 W, the increase at 1 W was greater than at a power output of 0.5 W. In terms of the number of laser irradiation applications, the most proliferation was observed in 2 and 3 application groups. The highest proliferation value was obtained with 1 W of power for 2 applications, and the lowest was with 3 W of power for 3 applications. Conclusions. The findings of this study show LT increased fibroblast cell proliferation, depending on the power output level of the laser and number of applications. In addition to the proliferation and mitotic activity of the fibroblast cells, the results demonstrate that LT could increase wound healing after oral surgery and periodontal treatments.