AIM: To investigate the effects of osteopontin (OPN) on cultured human dental pulp cells (hDPCs) in relation to adhesion, proliferation, differentiation, and mineralization. METHODOLOGY: Subcultured hDPCs isolated from healthy human wisdom teeth were inoculated on noncoated (NC, control) and OPN-coated nontissue culture-treated polystyrene plates (Non-TCPS). Cell adhesion and proliferation were analyzed by crystal violet staining and the CCK-8 assay, respectively. Expressions of cell adhesion-related protein markers such as FAK and Akt were visualized by the Western blot. Expressions of tooth-related mRNA markers were evaluated by qRT-PCR. The localization of the OPN protein in reparative dentine formation was visualized using immunofluorescence staining. Data were analyzed using the Tukey's multiple comparison test. RESULTS: Cell adhesion was significantly higher in OPN 1 μg/mL-coated group of the OPN, which is also comparable to that of the positive control (COL-1 group). Cell proliferation data showed a similar tendency. pFAK was activated as early as 3 h after cell inoculation in the 1 μg/mL-coated group of the OPN and COL-1 group. Moreover, the OPN stimulated hDPC mineralization in a time- and dose-dependent manner. Regarding the qPCR results, it was shown that OPN stimulated DMP-1 and CONCLUSION: Coated OPN promoted hDPC adhesion, proliferation, differentiation, and mineralization.