Citric acid with two carboxylic acid groups and an alcohol hydroxyl group was introduced into chitosan in order to develop a highly selective adsorbent for separation and recovery of In(III) and Ga(III) over Zn(II) and Cu(II) from waste of solar panels. Citric acid-immobilized chitosan derivative (CAC) was synthesized by heating chitosan dissolved in citric acid solution. The carboxylic acid of CAC was determined to be 5.77 mmo g(-1) by measuring the adsorption isotherm of NaOH. Adsorption experiments on CAC were carried out by a batch method at 303 K in order to examine the adsorption selectivity for In(III), Ga(III), Zn(II) and Cu(II) from 1.0 mol dm(-3) ammonium nitrate solution. CAC exhibited high adsorption selectivity for In(III) and Ga(III) over Zn(II) and Cu(II) at low pH. However, In(III) and Ga(III) were not separated from each other in the adsorption process. The maximum adsorption capacities for In(III) and Ga(III) were determined to be 0.72 mmo g(-1) and 0.98 mmo g(-1) respectively by measuring their adsorption isotherms at 303 K. Finally, the adsorbed In(III) and Ga(III) were eluted 100% with dilute hydrochloric acid, while only Ga(III) was eluted 100% with dilute sodium hydroxide solution. This indicates that In(III) and Ga(III) can be separated using 1 M NaOH solution in the desorption process. Consequently, CAC is very useful as a selective adsorbent for recovery and separation of In(III) and Ga(III) from zinc refinery residues and solar panel wastes.