The aim of this study was to investigate the protective effect of Andrographis paniculata extract (APE) against H2O2-induced oxidative stress in C2C12 skeletal muscle cells. APE exerted significant dose-dependent protective effect against H2O2-induced cell damage in C2C12 cells without cytotoxicity. The cells treated with APE concentrations of 1, 5, and 10 μg/mL had significantly lower reactive oxygen species (by 13.1%, 14.4%, and 17.3%, respectively) and malondialdehyde levels (by 23.3%, 33.4%, and 54.5%, correspondingly) than H2O2-treated cells. The H2O2 treatment decreased the content of glutathione (GSH), but the treatment with APE neutralized that adverse effect, increasing significantly GSH levels. In addition, we confirmed that H2O2 treatment of myotube cultures increased their lactate dehydrogenase (LDH) and creatine kinase (CK) activities, which are indicators of muscle damage. However, in the experimental myotube cultures, APE treatment significantly inhibited the LDH and CK activities, which were lower than those in the H2O2-treated mypotubes. In conclusion, APE treatment is of considerable significance as a therapy than can improve sarcopenia by attenuating oxidative stress in muscle cells.