The aim of this study is to evaluate the effects of lovastatin on the cell viability and osteogenic differentiation of human gingiva-derived stem cells. Stem cells were cultured in the presence of lovastatin at concentrations ranging from 2 μM to 6 μM. The morphology and cell viability were evaluated on days 2, 7, and 14. The alkaline phosphatase activity test and alizarin red-S staining were used to assess the osteogenic differentiation and mineralization. Quantitative real-time polymerase chain reaction was used to evaluate the mRNA levels of Runt-related transcription factor 2 (Runx2) and collagen I. Immunofluorescent assays were performed for Runx2 and collagen I, and protein expressions were measured, including those of Runx2 and collagen I, using Western blot analysis. The shapes of the cells in 2 μM lovastatin were similar to those of the untreated control group, showing revealed a spindleshaped, fibroblast-like morphology. However, the shapes of the cells in the 6 μM groups were rounder, and fewer cells were present. The CCK-8 values of 0 μM, 2 μM, and 6 μM at day 14 were 207.4 ± 15.5, 188.1 ± 13.3, and 166.0 ± 32.3, respectively (P<0.05). Decreased mineralization was noted in the 2 μM and 6 μM groups, when compared the 0 μM control. The relative alkaline phosphatase activity values of the 0 μM, 2 μM, and 6 μM groups were 100.0 ± 6.8, 70.5 ± 6.8, and 57.5 ± 5.8 on day 14, respectively. The expressions of Runx2 and collagen I by immunofluorescence decreased as the dose of lovastatin increased. The application of lovastatin produced decreased cell viability and decreased osteogenic differentiation in this experimental setting. It should be considered that the use of higher doses of statin may yield a negative effect on cell viability and differentiation of stem cells.