This study aimed to determine the most effective wavelength for the proliferation of Human Buccal Fat Pad Mesenchymal Stem Cells (BFPMSCs) in cell culture. These cells can be used for different purposes such as regenerative periodontal procedures. Materials and Methods: The wells containing BFPMSCs were subjected to laser irradiation at 635, 660, 808, and 980 nm wavelengths with 1, 1.5, 2.5, and 4 J/cm2 energy densities. Cell proliferation and viability were evaluated after 1, 3, and 5 days with the methyl thiazolyl tetrazolium (MTT) assay. Result: The proliferation rate of human Buccal Fat Pad Mesenchymal Cells (BFPMSCs) was increased on the first and third days at a wavelength of 808 nm and day five at a wavelength of 980 nm in comparison to the control group. Our findings distinguished that PBMT with 635, 660, 808, and 980 nm wavelengths increased the proliferation of BFPMSCs. Conclusion: The best laser radiation setting, which led to the highest proliferation rate of the cells, included a wavelength of 808 nm with 2.5 J/cm2 energy density.