Hazelnut shell was found quite effective on removel of different model textile dyes Adsorption process was controlled by both pseudo second order model and intra particular diffusion It was determined that adsorption process was of endothermic and spontaneous Hazelnut shell may be an eco-friendly solution for the treatment of effluents of industrial plants located in Turkey. The present study aimed at the utilization of hazelnut shells as a potential adsorbent for the treatment of synthetically prepared model textile dye solutions. Classical conventional adsorption procedure was followed to investigate the effects of initial dye concentration, adsorbent concentration, reaction time, initial pH, and temperature. The results showed that Langmuir isotherm identified the adsorption process of most of dyes better than Freundlich. Subsequently, kinetic calculations demonstrated that pseudo second order reaction model and intra particular diffusion model controlled the adsorption process for all dyes. Consequently, thermodynamic results showed that the adsorption process spontaneously occurred and it was of endothermic. Figure A. Effect ıf initial dye concentration on removal efficiency (%) Purpose: This study aims at the utilization of hazelnut shell for the treatment of industrial effluents to suggest an eco-friendly adsorbent. Theory and Methods: Classical batch adsorption process was performed to investigate the effects of initial dye concentration, adsorbent concentration, reaction time, initial pH, and temperature on removal efficiency. Results: This part can be divided into three groups as follows: (1) Isotherm studies showed that Langmuir model stated the adsorption process better than Freundlich model; (2) Kinetic studies showed that pseudo second order model and intra particular diffusion controlled the adsorption process; and (3) Thermodynamic studies showed that the adsorption process was of endothermic, spontaneous, and it had an increasing affinity with increasing temperature. Conclusion: Hazelnut shell was found quite effective on removal of synthetic model dye solutions. Given that Turkey has abundant sources of hazelnut, those shells can contribute to solution of problem coming from the industrial effluents.