Background: Increased reactive oxygen species disrupt the balance between osteoblasts and osteoclasts. Although the role of training (T) and vitamin D (VD) consumption in bone health has been shown, there is no accurate information on the role of these two interventions on the nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1), as an osteoclast marker. Objectives: Therefore, this study aimed to examine the effect of T and VD on NFATc1 gene expression in bone tissue of rats exposed to H2O2. Methods: Fifty adult male Wistar rats aged 8 - 10 weeks and weighing 180 to 220 g were randomly assigned to 10 groups including (1) control (C), (2) dimethyl sulfoxide + normal saline (sham; Sh), (3) 1 mmol/kg H2O2 (1H), (4) 1H+VD, (5) 1H+T, (6) 1H+VD+T, (7) 2 mmol/kg H2O2 (2H), (8) 2H+VD, (9) 2H+T, and (10) 2H+VD+T. The research protocol lasted eight weeks to implement. The levels of NFATc1 gene expression were measured by qRT-PCR. Results: Based on the results, 1H and 2H significantly increased NFATc1 gene expression levels (P = 0.001). However, T (P = 0.001), VD (P = 0.001), and VD+T (P = 0.001) reduced NFATc1 gene expression in the bone tissue of rats exposed to 1 and 2 mmol H2O2. Also, NFATc1 gene expression was significantly lower in the 1H+VD+T group than in the 2H + VD group (P = 0.03). Conclusions: It seems that T and VD consumption both alone and synergistically have a reducing effect on NFATc1 as an osteoclast index in rats exposed to 1 and 2 mmol/kg H2O2.