In the present study, calcined and acid activated adsorbents were prepared from Ethiopian kaolinite clay.The adsorbent preparations were conducted by thermal and chemical(phosphoric acid) activation processes. The prepared adsorbents and raw kaolinite clay were analyzed for morphological and chemical characterization using XRF, FTIR, XRD and SEMinstrumental techniques. From the oxide composition analysis, the ratio of SiO2/Al2O3was 4.08 foracid activated kaolinwhich is higher than the expected pure kaolinite standard which allows us to classify the kaolin clay as a zeolite material. The batch adsorption process, basic operation parameter (such as initial concentrations of dye, temperature, contact time, and pH of the solution) were examined.It was found that a maximummethylene blue dyeremoval efficiency of 90.04% and 93.6% were achieved for calcined and acid activated kaolin adsorbent respectively at; initial concentration of 20 mg/L, temperature of 30℃, contact time of 60 min, solution pH of 9 and adsorbent dose 1g/100ml.Furthermore, the adsorption kinetic models, the adsorption isotherm models and the thermodynamic parameters were determined for the batch adsorption experiments.The calculatedΔG o for acid activated and calcined kaolin adsorbent were recorded as -0.958, 1.029 and 2.767kJ/mol and 0.244, 2.019, and 3.158 at 30 o C, 50 o C, and 70 o C, respectivelyfor 20 mg/L of dye concentration and solution pH of 9.This suggests that, the thermodynamic behavior at lowest temperature is more feasible and spontaneous as compared with the higher temperature. In addition, the ∆Hᵒ and ∆Sᵒ value is recorded a negative value suggest that, the adsorption is exothermic.Moreover the equilibrium data was fittedwith the Freundlich and Langmuir isotherm models,and found that Langmuir model fitted very well for both adsorbents. Finally, the rate of the adsorption process was investigated using Pseudo first order and Pseudo second order kinetic models, and found to be well fitted with Pseudo first order for calcined kaolin adsorbentand Pseudo second order kinetic models for acid activated kaolin adsorbent. From these results it can be conclude thatacid activated kaolin adsorbent has a high capacity for the removal of dyes in industrial wastewater. Keywords:Kaolin, Acid activation, adsorption,methylene blue dye