Objective: Distinct cells respond differently to low-level laser therapy (LLLT), while the exact molecular mechanisms involved in cell proliferation or growth inhibition, after light stimulation remain poorly understood. Although LLLT has shown promising results in accelerating wound healing and preventing or treating oral mucositis, there is no evidencebased consensus of what this energy could cause in cancer cells. This should be highly pondered when an oral cancer patient is treated with LLLT due to oral mucositis, for example. Method: Two tongue squamous cell carcinoma cell lines (SCC9 and SCC25) were utilized to find the effect of low-level laser irradiation on the Akt/mTOR signaling pathway. Laser irradiation (660 and 780 nm) consisted on 40 mW of power and energy densities of 2, 3 and 6 J/cm2. After a single irradiation the most significant energy densities found with MTS assay were employed to analyze Akt/mTOR signaling pathway related proteins through immunofluorescence and western blotting.