Sandwich-like MgO@Carbon (MgO@C) nanocomposoites were fabricated using a one-pot hydrothermal route for the removal of organic dyes. The effects of contact time, pH value, carbon thickness, inorganic ions, and temperature on the sorption capacity of MgO@C were investigated. Compared with pure MgO nanoparticles and carbon bulks, the as-obtained sandwich-like MgO@C exhibited much higher sorption capacity for methyl orange due to the enhanced electrostatic interaction between anionic dye molecules and positively charged MgO@C nanocomposite. The sorption capacity of MgO@C increased with the increase of specific surface and pore volume, and the MgO@C-3 with a carbon thickness of around 5 nm exhibited the highest adsorption efficiency. The adsorption isotherm and kinetics of dye over MgO@C were well fitted by the Langmuir isotherm model and pseudo-second-order adsorption model, respectively. Further investigation indicated that the sorption process of methyl orange over sandwich-like MgO@C was controlled by the external mass transfer and intraparticle diffusion, and was a spontaneous and exothermic adsorption process.