The mechanism of steroid-associated femoral head necrosis remains unclear. The present study investigated the role of microRNA-23a-3p (miR-23a-3p) in the incidence of osteonecrosis in a rat model. An miR-23a-3p mimic, an inhibitor and a negative control were transfected into bone mesenchymal stem cells using a lentiviral vector, and then injected into the steroid-induced femoral head necrosis model. Osteonecrosis incidence was assessed by micro computed tomography and histopathology. Low-density lipoprotein receptor-related protein 5 (LRP-5) expression was assessed by immunohistochemistry. The results demonstrated the incidence of osteonecrosis decreased in the miR-23a-3p inhibitor group compared with the miR-23a-3p mimic group (18.2% vs. 75%; P<0.05). The ratio of bone volume/total volume and trabecular thickness were significantly increased in the miR-23a-3p inhibitor group compared with the miR-23a mimic group. The expression level of LRP-5 was higher in the miR-23a-3p inhibitor group. The present study indicated that miR may provide a novel and alternative approach for understanding the mechanism underlying steroid-associated necrosis of the femoral head.