Canonical Wnt signaling is critical for the control of osteoblast differentiation in human mesenchymal stem cells. MicroRNAs (miRs) are essential regulators of cell differentiation by post-transcriptional regulation of target gene expression. The aim of the present study was to investigate the molecular mechanism by which miR-142-3p promotes osteoblastic differentiation. using the human fetal osteoblastic 1.19 (hFOB1.19), real-time PCR and western blot analysis. Results showed an increased expression of miR-142-3p during osteoblast differentiation in the mesenchymal precursor cell line, hFOB1.19. In addition, the ectopic overexpression of miR-142-3p promoted hFOB1.19 differentiation, whereas the inhibition of miR-142-3p repressed differentiation. The expression of miR-142-3p was positively correlated with P-catenin, an important protein in Wnt signaling. The adenomatous polyposis coli (APC) gene was a direct target of miR-142-3p, whereby miR-142-3p promoted Wnt signaling through inhibition of APC, leading to accumulation and nuclear translocation of p-catenin. Therefore, miR-142-3p may be an essential mediator of osteoblast differentiation and a new therapeutic strategy for osteogenesis disorders.