In the present study, a low-cost adsorbent derived from Moringa peregrina plant has been used for its ability to remove two common textile dyes, namely Methyl Orange (MO) and Reactive Red 198 (RR-198) from aqueous solutions. The effect of various operating parameters such as initial concentration of dye (10-150 mg L-1), contact time (10-150 min), adsorbent dosage (1-13 g L-1) and pH (2-11) is investigated. At an optimum pH of 2, approximately 96% removal of dye (50 mg L-1) is obtained for an adsorbent dose of 7.0 g L-1 after a 70 min contact time. The equilibrium assessment reveals that the Langmuir model is better than Freundlich model for the experimental data. The thermodynamic properties (Delta G degrees, Delta H degrees and Delta S degrees) show that the adsorption of RR-198 and MO dyes onto Moringa peregrina tree shell ash (MPTA) is spontaneous, endothermic and feasible in the temperature range of 293-313 K. Also, the magnitude of enthalpy change indicates that the adsorption is physical in nature. Finally it can be concluded that the MPTA can be used as a low-cost adsorbent for the removal of different concentrations of anionic dyes from aqueous solutions.