Reactive blue-13 (RB-13) dye was removed using magnetic activated carbon (MAC) in the batch mode. The effect of the initial mass of the adsorbent (1-25 g/L), initial RB-13 concentration (10-50 mg/L), solution pH (2-12), temperature (298-333 K), and contact period (0-120 min) on the removal of RB-13 dye was explored. The isoelectric point study was also performed for determining the pH at which the net charge on the surface of MAC was equivalent to zero. The Langmuir adsorption isotherm showed the best correlation at all temperatures. The adsorption kinetics was best described by a pseudo-second-order model. Thermodynamic study concluded that the adsorption of RB-13 dye onto MAC took place exothermically and the process was spontaneous.