In this study, the adsorption properties of activated almond shells for methylene blue (MB) were investigated. For this aim raw almond shells (RAS) were activated with concentrated sulfuric acid. Activated almond shell (SAS) and raw almond shells (RAS) were characterized with FTIR, SEM and BET analysis. After activation, larger and deeper pores similar to chamber were formed and increase in BET surface area and adsorption rate and also new functional groups were observed. Effects of pH, initial concentration of dye and adsorbent dose on adsorption of MB were studied. Adsorption studies were fitted Langmuir isotherm and pseudo second order kinetic models. Experimental results showed that activated almond shells were not affected pH of solution and adsorption capacity were highly increased and it was calculated as 131.58 mg g-1 from Langmuir isotherm. It was observed that the activated almond shells could be used with high efficiency in a wide pH and concentration ranges and SASs could be desorbed and reusable without losing their activity. As a results, SAS could be used an effective adsorbent for the removal of basic dyes like MB at a wide pH and dye concentration range.