The structural, electronic and adsorption properties of chlorine on pristine, Sn, Al and F substituted In 2 O 3 nanostructures are successfully optimized and computed using density functional theory along with B2LYP/ LanL2DZ basis set. The electronic properties of pristine, Sn, Al and F substituted In 2 O 3 nanostructures are discussed in terms of ionization potential, HOMO-LUMO gap, and electron affinity. The dipole moment and point symmetry group of In 2 O 3 nanostructures are also reported. The structural stability of pristine, Sn, Al, and F substituted In 2 O 3 nanostructures are investigated in terms of formation energy. The adsorption properties of chlorine on indium oxide are studied and the most appropriate adsorption sites of Cl 2 on In 2 O 3 nanostructures are reported. The adsorption properties of hydrogen on In 2 O 3 nanostructures are also investigated and it inferred that In 2 O 3 exhibits good sensing characteristics towards hydrogen. The adsorbed energy, HOMO-LUMO gap, Mulliken population analysis and average energy gap variation are used to identify the prominent adsorption site of Cl 2 on In 2 O 3 material. The substitution of F in In 2 O 3 nanostructure enhances the Cl 2 adsorption properties in the mixed gas atmosphere.